How Do *You* Calculate YTU's Budgets?

[RainOfSteel]

EDIT -- 2011-02-12

The code-blocks around the budget data had broken somehow on posts #1 and #17. I fixed them.

Please remember that the data shown below here in post #1 was the result of an error in my original SQL code. Better data appears in post #17.

-------------------------

I've been asked now in a couple of emails and once on a different topic here to state how I calculate my budgets.

It's farily specific to MTU, and since it was pretty off topic where I just answered (over in The Fleet), so I decided to repost here, and also see if a more on-topic thread title would go further.
-------------------------

Originally posted by Sigg Oddra:
RainOfSteel, can I ask how you calculated the Spinward Marches budget?

I used the GT:Far Trader GWP calculation exactly. Population * Per Capita Income.

However, since I used CT/T20, I did a very WAG (Wild A@@ Guess) conversion of the Base Per Capita Income table into CT/T20:Credits from GT:Credits. It was, basically, my best guess. I think my guesses make my values higher than other's figures. However, given what I'm finding out about IN budgetary needs, that's not a bad thing.

The data came from a nice Access 95 database over at Doug's World Software Page. I imported it into Access 2000.

There was only one table in it, pretty much a flat-file copy of an extended UWP.

The one drawback, it said it was a Classic Traveller database, but the allegiance codes were all MT. I had to alter allegiance codes en masse in several sectors in order to get things straightened out. The rimward border along the Vargr Extents is somewhat suspect in correct Allegiance coding, and I apologize about that (Maybe 100 worlds, tops, that have bad coding).

I added a table to support the Base Per Capita Income Table.

Then I created an SQL Query to list the GWP of every world with an Allegiance Code of "Im".

Then I created an SQL Query to list the MWC of each world that draws on the GWP query.

Then I ran MTU's taxation system percentages (a variant of Richard Aiken's system; He's an active member of the TML).

Basically, of the GWP of each Member World, the Imperium taxes 2%, and 4% during General War; this value is the Member World Contribution (MWC).

Of the MWC, the Member World's Noble (Marquis or Baron), keeps 66% to spend on defense and development locally, retains 1% as a Noble Stipend, and passes 33% on to the Subsector level.

Each Subsector keeps 66% of the Member World Subsector Contributions (MWSuC) for itself, 1% for the Subsector Noble Stipend, and passes on 33% to the Sector.

Each Sector keeps 66% of the Subsector Contributions for itself, 1% for the Sector Noble Stipend, and passes on 33% to the Imperial level. I'm debating on whether to give .2 to .5 of a percentage point from each Sector's 66% share to the Archduke of the Domain of that Sector (in order to allow the Archdukes sufficient funds beyond the personal to avoid embarrassing the rest of the aristocracy with improvished major nobles hanging around).

Then I created several SQL Queries to assemble the values found in the MWC query. One to list all world's values for a Subsector. One to list the summary of a Subsector. One to list all Subsector summaries in a Sector. One to list the Sector summary. One to list the Sector Summary for all Sectors with "Im" Allegiance Code worlds. One to list the Imperial summary.

I get the Spinward Marches figure out of the Sector Summary. The specific queries (that is, the ones that list values for a specific Sector or Subsector) are all "parameterized", and so I just type in whatever Sector or Subsector name I want (into the correct query, of course), and out pops the values for that region of space.

If you don't have MS Access 95 or later, the website above has an Excel 97 spreadsheet copy of the info. With work, a free SQL database could be located and installed (Firebird, Mimer-SQL, etc.), and a simple database and table could be created. Some ODBC work could import the Excel 97 data into that new database, were you could work the data in whatever manner you choose.


In case it may be of interest, the results for the Imperium are:

SectorName            ImperialBudget           Worlds   % of Total Budget    % of Total Worlds
Hinterworlds          Cr257,282,784            2        0.00001205%          0.02272469%
Empty Quarter         Cr2,750,582,732,740      134      0.12887121%          1.52255426%
Trojan Reaches        Cr4,250,613,777,959      24       0.19915117%          0.27269628%
Glimmerdrift Reaches  Cr7,771,035,342,682      42       0.36409113%          0.47721850%
Reft                  Cr9,066,874,871,961      38       0.42480423%          0.43176912%
Spinward Marches      Cr20,809,666,622,299     272      0.97498141%          3.09055789%
Corridor              Cr27,891,099,627,312     267      1.30676305%          3.03374617%
Zarushagar            Cr29,537,394,019,581     481      1.38389579%          5.46528804%
Reavers Deep          Cr31,246,132,802,561     65       1.46395418%          0.73855244%
Diaspora              Cr33,759,407,574,461     328      1.58170697%          3.72684922%
Verge                 Cr35,591,018,202,632     222      1.66752219%          2.52244063%
Magyar                Cr44,136,508,587,169     132      2.06789835%          1.49982956%
Ley                   Cr48,359,710,678,244     316      2.26576521%          3.59050108%
Delphi                Cr52,696,873,126,330     293      2.46897139%          3.32916714%
Alpha Crucis          Cr54,253,792,864,735     78       2.54191671%          0.88626292%
Antares               Cr62,039,263,793,251     465      2.90668417%          5.28349051%
Fornast               Cr71,618,788,782,416     517      3.35550726%          5.87433246%
Gushemege             Cr72,674,552,114,430     528      3.40497223%          5.99931826%
Deneb                 Cr73,194,085,058,765     326      3.42931356%          3.70412453%
Core                  Cr121,918,592,450,938    545      5.71217035%          6.19247813%
Lishun                Cr127,454,085,098,731    601      5.97152109%          6.82876946%
Vland                 Cr136,578,711,075,284    486      6.39903109%          5.52209976%
Daibei                Cr142,787,286,095,065    430      6.68991731%          4.88580843%
Dagudashaag           Cr143,163,067,082,980    559      6.70752352%          6.35155096%
Ilelish               Cr173,135,740,758,740    450      8.11181318%          5.11305533%
Old Expanses          Cr189,772,522,791,421    401      8.89128521%          4.55630042%
Massilia              Cr195,387,775,965,971    519      9.15437291%          5.89705715%
Solomani Rim          Cr222,520,047,447,435    280      10.42558310%         3.18145665%
Grand Total           Cr2,134,365,486,628,880  8801     100.00000000%        100.00000000%

Note that the Imperial Budget column lists Sector Contributions to the Imperial level, not Sector Budgets.


And of course, lazy b@tt that I am, I still haven't added Trade Classification modifiers in.




EDIT: 03/02/2005: 22:40 MST
---------------------------
I have now added in the Trade Classification Modifiers as specified in GT: Far Trader. This can be found at: Topic: How Do *You* Calculate YTU's Budgets? Posts #17 & #18

NOTE: It's important to note that the above data was far too low due to an error on my part. My most sincere apologies.

 

[mike wightman]

Excellent work

I can see now why the Imperium wants to hang on to the Occupied Solomani Sphere worlds

 

[RainOfSteel]

Originally posted by Sigg Oddra: Excellent work

Ah, shucks. Thanks!

Originally posted by Sigg Oddra:
I can see now why the Imperium wants to hang on to the Occupied Solomani Sphere worlds

Why yes, I noticed that myself.

 

[jatay3]

I can see now why the Imperium wants to hang on to the Occupied Solomani Sphere worlds
---------------------------------------------
That is part of the reason.
Also an Empire can't afford to let it be said that it can be beaten

 

[Malenfant]

Also an Empire can't afford to let it be said that it can be beaten

Well yeah. Look what happened last time the Solomani won...

 

[Straybow]

So these figures are 33% of 33% of 33% of aggregate MWC (which is 2% of aggregate GWP)? Therefore Imperial share of MWC amounts to only 3.6% of MWC which is 3.6 times the MW Noble's stipend.

So dividing the given budget by (3.6 times the number of worlds listed) gives the average noble's stipend: 67 billion credits!!

The suffering Baron of one of the two worlds in the Hinterlands would have a stipend of a mere 36 MCr. Poor dear. Marquis of an ancient Vilani holding may have a stipend of 78 GCr. Ruler of an average Solomani world: 221 GCr!

Kinda paints a different picture of what being an Imperial Noble means.

 

[RainOfSteel]

Straybow,

Yes.

Note: Various IMTU terms follow, and the context of the discussion is also IMTU.

The Ruling Nobility, as I put it, those that have an Imperial Government District (Imperium, Domain, Sector, Subsector, or World) among their Title Properties (all the properties, concrete or abstract, that belong to the Title, rather than the sophont upon which the Title is Installed), all receive such a stipend, a "paycheck" drawn from taxation.

However, as is recently mentioned by GT:Nobles (although it says it somewhat differently), and was already assumed by myself, any particular noble's personal funds aren't always spent on whatever the noble wants. Every noble has many, many obligations passed down to them by previous Title Holders, and may have obligations imposed upon them from their Title Superiors (which themselves may have stacked up going back a long time), all of which must be discharged successfully under the rules of Noblesse Oblige.

Other nobles, Service, Rank, and Family, all may or may not have wealth. They do have Title Properties (companies, starships, financial instruments, etc.), just like a Ruling Noble, but they get no stipend from taxation like the Ruling Nobility do . . . "sort of", because in all cases a Title Creator (Emperor or Archduke) must endow any newly created Title with Title Properties comensurate with the status of the Title. It is a duty of Noblesse Oblige (one of the most serious), to nuture and develop the Title Properties belonging to the Title. Since most nobles pursue this assiduously<sp>, they usually accumulate extra wealth, and this increases the size and value of the Title Properties over time (in most cases).

Nobles who run out the value of their Title Properties are an embarressment to the rest of the nobility. They don't get invitations to parties and have trouble getting audiences with important Ruling Nobles.

Ruling Nobles who even begin to run down their Title Properties are chastened and corrected in their errors by their Title Superior, and failing that, up the chain of command, all the way to the Emperor (if the case is important enough, see Gateway to Desitny and the campaign waged by the Sector/Domain combined Duke/Archduke to "run down" the Sector).

 

[soloprobe]

Guys,

Would this be like the world GNP calculations in book 2 of STRIKER?

 

[robject]

Soloprobe,

Similar in idea, I think. If I recall correctly, the Striker GNP calculations made too much money available. At least from a shipbuilding standpoint. I think.

Rob

 

[robject]

Originally posted by Straybow:
So these figures are 33% of 33% of 33% of aggregate MWC (which is 2% of aggregate GWP)? Therefore Imperial share of MWC amounts to only 3.6% of MWC which is 3.6 times the MW Noble's stipend.

So dividing the given budget by (3.6 times the number of worlds listed) gives the average noble's stipend: 67 billion credits!!

The suffering Baron of one of the two worlds in the Hinterlands would have a stipend of a mere 36 MCr. Poor dear. Marquis of an ancient Vilani holding may have a stipend of 78 GCr. Ruler of an average Solomani world: 221 GCr!

Kinda paints a different picture of what being an Imperial Noble means.

Egads.

I never worried too much about nobles having access to cash, but that's ridiculous!

Talk about your trillion-credit squadrons...

 

[RainOfSteel]

robject,

I've done some preliminary calculations for naval budgets (very preliminary). But at the Imperial level, the amount of money necessary to field the entire IN is going to be staggering. Plus, of course, there is everything else that requires funding, too.

IMTU: At the Subsector level, Counts will be in charge of deploying the Subsector Navies. Deploying enough CAs into strategic reserve pools, plus enough CLs, DDs, and SDBs to patrol all worlds, with reserves to cover for refitting and maintenence, transit to and from station, etc., that alone is going to be very expensive.

Just by example. There isn't any way the Spinward Marches (one of the poorest Sectors in the Imperium) could hope to pay for IN resources to challenge the Zhodani. They rely on additional funds provided from the Imperial level.

As for how fabulously wealthy the Ruling Nobility are (in the tax chain and receiving stipends from that taxation), why, I believe that's the way it should be. Of course, the total number of Dukes, Counts, and Margraves in charge of High Pop worlds is really quite small in comparison to the number of other nobles in the Imperium as a whole (the majority aren't nearly as wealthy, save those families in charge of the really big Sector Corps and Megacorps).

 

[robject]

Yeah, I don't know how much the naval budget is. I don't remember quite how many ships are included (non-colonial forces I suppose). All I remember is that there are around 1000 butt-kicker ships in the IN... not including support ships, I presume.

I'm going to re-read your post now and think about this. This is YTU, but the conclusion is pretty general.

Population x Per Capita is the way to do it.

Lessee if I can do a wild-a@@ guess.

Assumption #1: The median & average Traveller world is starport class C, TL 12.

Conclusion #1: Thus the median & average world 'credit' is worth 0.5 Cr.

Assumption #2: The median & average SOC is 7.

Conclusion #2: Hence the median & average wage is about 20,000 local credits per year.

Conclusion #3: The median & average per capita is 0.5 x 20,000 = Cr 10,000.

Assumption #3: There are 15 trillion sophonts in the Imperium.

Conclusion #4: Thus, the total Imperial Product is 150,000 trillion Cr per year...

Oh my. That's a lot of dough.

 

[rancke]

Originally posted by robject:
Yeah, I don't know how much the naval budget is. I don't remember quite how many ships are included (non-colonial forces I suppose). All I remember is that there are around 1000 butt-kicker ships in the IN... not including support ships, I presume.

Ah, that's a thousand butt-kicker ships (aka cruisers and up) per sector [Rebellion Sourcebook]. Depending on just how you interpret that it could mean either 18,750, 20,000, or 28,000 capital ships for the whole Imperium. Personally I go for the 20,000 ship figure (I assume the figure is for a full 16-subsector sectorand divide by 16 to get 62.5 ships[*] per subsector. Since the Imperium has about 300 subsectors that could mean 18,750 ships, but I make it 62.5 ships per fleet instead, and since the Imperium has 320 fleets the figure becomes 20,000).

[*] On the average, of course.

This would be for the regular navy. The reserve fleets and the duchy fleets (if they exist) are not included in the figure.


Hans

 

[Psion]

Anyone look and see how these numbers compare to TL-compensated numbers from TCS forumlae?

(I did up such numbers for just the hi pop worlds in the ley sector once. I was amazed at how many dreadnaughts they could supposedly field.)

 

[robject]

Originally posted by rancke:

Ah, that's a thousand butt-kicker ships (aka cruisers and up) per sector [Rebellion Sourcebook].
[...]
Personally I go for the 20,000 ship figure
[...]
[ = 320 fleets x 62.5 ships per fleet ]

Hans

Yowza!! By Estigarribia's Nose, you're right. I can't believe I read that incorrectly... well that's more like it.

 

[flykiller]

Anyone look and see how these numbers compare to TL-compensated numbers from TCS forumlae?

didn't get all involved and precise (in a fantasy game?) but came up with thousands of capital ships plus support, troop transport, etc for the spinward marches. a good rule of thumb is fifteen times shipyard capacity. if one uses TCS construction rules it's not possible to spend the money as fast as it comes in.

 

[RainOfSteel]

Ah yes, well now, time to get down to business.

When I originally started this thread, lo those many years ago (<cough, cough />), I mentioned I hadn't entered in the GT: Far Trader "Trade Code Modifiers" to GWP.

However, first a bit of diversion.


Many months ago, I, Ahem, reviewed the SQL involved . . .

Well, life can sometimes be a little embarrassing.

I had inverted two columns in my queries, basically entering in the 33% share in the wrong slot (calculated column), and the 66% share in the wrong slot.

Oops.

<la, la, la />

This made the Imperial side of things much richer, and the sector side, of course, poorer.

I cleaned that up, and a couple of other areas, as well. Needless to say, I was pretty annoyed with myself, and wandered off and did other things.

And now back to your regularly scheduled topic . . .


A couple of days ago, I began the assault on adding the effects of Trade Code Modifiers (TCMs) on GWP values.

Ah, it was a contentious battle, with fractional-C VBA code weapons and SQL shields aplenty . . . <cough, cough /> "Waiter! Get that man a glass of water!"

Relationally based databases like MS Access have a number of nice "aggregate" functions built in that summarize data, like SUM, AVG, and COUNT (among others). However, TCMs are decimal values that are multiplied. You can multiply them all together in any order you want, of course . . . but SQL will not do it for you.

It was pretty simple to write a VBA function that would take a world's Primary Key and loop through the list of Planetary Trade Codes, and link that in with the master list of Trade Codes (and the Per Capita Modifiers associated with those Trade, per GT: Far Trader).

All except the part about the Planetary Trade Codes. They certainly weren't in the Remarks field in my data, and even if they had been, that data wouldn't qualify as relationally stored, anyway (multiple values in a single column of a row, blasphemy!), and nothing but a nightmare VBA function would help out at that point.

Instead, I created a new table to hold all the Trade Codes from each world. I wrote sixteen INSERT queries, and loaded the Table (and no, it didn't work the first time, or even the second time, when the Ag codes got loaded in twice, somehow . . . even though I was running the load from code and there was no duplicate use of the Ag code insert query . . . go figure).

I wrote up the VBA query that would loop through each world's Trade Code Per Capita Modifiers, multiplying them all together. Running that 15,000+ for the rows in my DB took ten minutes on my PC (it's a clunker), so I created an extra (yes, it's de-normalized) column in my main world's table (creatively named, "Data"; I left the table name alone from the original .mdb I received), and ran an UPDATE to load the information (which took 10 minutes each, and required three tries to get right, because that all happened interspersed among the above).

Anyway, once it was loaded in, and I had put in the TotalTradeMultiplier value into the bottom-level GWP calculation for all worlds, I fired it up, and finally acquired the new, more up to date, data. Having the totaled value pre-loaded did wonders for performance (but will, of course, require extra updating work).

So the total loss to the Imperium after adding in the effects of Trade Code Modifiers is a little over 500 Trillion Credits at the Member World Level, and approx 227 Trillion Credits to the Imperial Annual Budget at the top.

And, without further ado, the new data.

SectorName            ImperialContribution     Worlds   % of Total Budget   % of Total Worlds
Hinterworlds                  Cr658,643,927       2       0.00000793%          0.02291476%
Empty Quarter          Cr11,154,374,959,647     134       0.13421566%          1.53528873%
Trojan Reaches         Cr17,684,214,311,367      24       0.21278633%          0.27497709%
Glimmerdrift Reaches   Cr30,919,660,102,514      42       0.37204259%          0.48120990%
Reft                   Cr36,607,012,137,218      38       0.44047598%          0.43538038%
Spinward Marches       Cr84,649,680,408,615     272       1.01855215%          3.11640697%
Corridor              Cr103,759,038,479,270     267       1.24848660%          3.05912007%
Zarushagar            Cr116,270,705,020,851     481       1.39903394%          5.51099908%
Diaspora              Cr129,229,387,999,514     328       1.55496004%          3.75802016%
Reavers Deep          Cr130,436,609,538,005      65       1.56948600%          0.74472961%
Verge                 Cr165,997,597,868,617     222       1.99737564%          2.54353804%
Ley                   Cr173,082,406,604,342     316       2.08262401%          3.62053162%
Delphi                Cr178,659,789,461,126     293       2.14973419%          3.35701192%
Magyar                Cr179,645,380,169,722     132       2.16159336%          1.51237397%
Alpha Crucis          Cr181,687,544,966,978      78       2.18616583%          0.89367553%
Antares               Cr205,320,520,075,476     465       2.47053096%          5.32768103%
Gushemege             Cr269,885,384,798,176     528       3.24741141%          6.04949588%
Fornast               Cr311,840,615,273,143     517       3.75224013%          5.92346471%
Deneb                 Cr321,902,828,556,431     326       3.87331429%          3.73510541%
Vland                 Cr502,750,924,121,633     486       6.04937940%          5.56828598%
Core                  Cr509,760,836,172,946     545       6.13372657%          6.24427131%
Dagudashaag           Cr513,592,931,671,834     486       6.17983648%          5.56828598%
Lishun                Cr531,010,909,173,969     601       6.38941929%          6.88588451%
Daibei                Cr573,198,884,881,162     430       6.89704854%          4.92667278%
Ilelish               Cr722,691,561,418,506     450       8.69582776%          5.15582035%
Old Expanses          Cr725,806,421,719,379     401       8.73330750%          4.59440880%
Massilia              Cr746,849,300,009,082     519       8.98650714%          5.94637947%
Solomani Rim          Cr836,389,963,025,072     280       10.06391031%         3.20806599%
                    Cr8,310,785,141,568,520     8801      100.0000000%         100.000000%

 

[RainOfSteel]

Here's a slightly different view.

Remember, "Duke" IMTU is "Sector Duke" in the OTU.

NOTE: Some Sectors, like the Hinterworlds, don't have an actual Duke or even administration, being controlled from elsewhere. My data is organized geographically, not by managing divisions.

SectorName            ImperialContribution     SectorTotalCollection      DukesStipend            Subsectors
Hinterworlds                  Cr658,643,927              Cr329,321,964              Cr9,979,453       1
Empty Quarter          Cr11,154,374,959,647        Cr5,577,187,479,824        Cr169,005,681,207       9
Trojan Reaches         Cr17,684,214,311,367        Cr8,842,107,155,684        Cr267,942,641,081       2
Glimmerdrift Reaches   Cr30,919,660,102,514       Cr15,459,830,051,257        Cr468,479,698,523       4
Reft                   Cr36,607,012,137,218       Cr18,303,506,068,609        Cr554,651,699,049       5
Spinward Marches       Cr84,649,680,408,615       Cr42,324,840,204,307      Cr1,282,570,915,282      14
Corridor              Cr103,759,038,479,270       Cr51,879,519,239,635      Cr1,572,106,643,625      16
Zarushagar            Cr116,270,705,020,851       Cr58,135,352,510,426      Cr1,761,677,348,801      14
Diaspora              Cr129,229,387,999,514       Cr64,614,693,999,757      Cr1,958,021,030,296      12
Reavers Deep          Cr130,436,609,538,005       Cr65,218,304,769,003      Cr1,976,312,265,727       8
Verge                 Cr165,997,597,868,617       Cr82,998,798,934,309      Cr2,515,115,119,221      12
Ley                   Cr173,082,406,604,342       Cr86,541,203,302,171      Cr2,622,460,706,126      14
Delphi                Cr178,659,789,461,126       Cr89,329,894,730,563      Cr2,706,966,506,987      15
Magyar                Cr179,645,380,169,722       Cr89,822,690,084,861      Cr2,721,899,699,541       9
Alpha Crucis          Cr181,687,544,966,978       Cr90,843,772,483,489      Cr2,752,841,590,409       5
Antares               Cr205,320,520,075,476      Cr102,660,260,037,738      Cr3,110,916,970,841      16
Gushemege             Cr269,885,384,798,176      Cr134,942,692,399,088      Cr4,089,172,496,942      15
Fornast               Cr311,840,615,273,143      Cr155,920,307,636,572      Cr4,724,857,807,169      16
Deneb                 Cr321,902,828,556,431      Cr160,951,414,278,216      Cr4,877,315,584,188      15
Vland                 Cr502,750,924,121,633      Cr251,375,462,060,817      Cr7,617,438,244,267      16
Core                  Cr509,760,836,172,946      Cr254,880,418,086,473      Cr7,723,649,032,923      16
Dagudashaag           Cr513,592,931,671,834      Cr256,796,465,835,917      Cr7,781,711,085,937      16
Lishun                Cr531,010,909,173,969      Cr265,505,454,586,985      Cr8,045,619,835,969      16
Daibei                Cr573,198,884,881,162      Cr286,599,442,440,581      Cr8,684,831,589,109      16
Ilelish               Cr722,691,561,418,506      Cr361,345,780,709,253     Cr10,949,872,142,705      14
Old Expanses          Cr725,806,421,719,379      Cr362,903,210,859,690     Cr10,997,066,995,748      16
Massilia              Cr746,849,300,009,082      Cr373,424,650,004,541     Cr11,315,898,484,986      16
Solomani Rim          Cr836,389,963,025,072      Cr418,194,981,512,536     Cr12,672,575,197,350      13
                    Cr8,310,785,141,568,520    Cr4,155,392,570,784,270    Cr125,920,986,993,462     341

 

[Whipsnade]

Holy Guacamole! That is a lot of dough!

Barons with billions?!!? Yikes!

Now I know why Mr. Miller has never answered any of the economics questions: His OTU version of the Imperium simply cannnot exist with that much money in hand.

Nice numbers, RoS. They are certainly food for thought.


Sincerely,
Bill

 

[robject]

I vaguely recall something on the TML (lo these many years ago...) recalling someone telling Marc how rich the TCS budget calculations (or was it Striker?) made the Imperium. Apparently, Marc was not amused.

I wonder... if there really is 1000 butt-kicker (BK) ships per sector, what kind of budget is implied by that?

Assumption 1: the average cost for BK ships (throw in the support ships for free) is BCr10.

Conclusion 1: the average sector naval assets are worth TCr10.

Conclusion 2: the total Imperial naval assets are worth TCr200.

So the question is: is that all from the Imperium's 3.5% cut of the average 3% MWC, or do the sectors contribute too? I'd have to assume that everyone pitches in somehow...

(If I had to handwave things more, I'd say the Imperium doesn't levy taxes on member worlds, but instead sells "services" to them, relating to interstellar trade and protection perhaps. A racket?)

Well, if the worlds' combined GDP is QCr8, then 2.5% of that goes into the Imperial fleet. That's not unreasonable...

Or did I screw up my guesstimation?