These numbers show that there are some real problems with leaning too hard on the T5SS data for sophont demographics.
First, population notations are very inconsistent right now and should not be considered comprehensive. If a canonical text source mentioned a significant non-human population, that probably ended up in the T5SS data. But the vast majority of Imperial worlds have never been touched by canon, and no one has yet done a systematic sweep through the data to seed non-human populations. Minority Vargr populations should be more common in the coreward sectors, Aslan populations in Daibei and maybe Magyar. So on and so forth.
Second, several large non-human populations appear to be thinly scattered throughout Imperial space. Vargr, Bwaps, Aslan, and Suerrat are all good examples. While they might not appear concentrated in large enough numbers to show up in the remarks section of a mainworld, in aggregate they probably represent significant populations across the Imperium.
Here's a quick back-of-the-envelop of this second case.
Imperiallines 7 contains some interesting hints at the demographics of the Imperium, noting that "While the Imperium was created by Humaniti and continues to be dominated by humans, roughly half of the nobles in the Imperium are non-Humans or minor Human races that have diverged significantly from the Sylean, Vilani, and Solomani norm, and the Human half includes those minor races that remain part of the main Human genetic pool."
Now, the composition of the nobility does not necessarily reflect the overall composition of the population. My guess is that the nobility intentionally overrepresents non-human sophonts, but that's only a guess.
But Imperiallines gives us some sense of proportions of non-human races within the larger non-human group: "In general, no other race comprises more than 5% of the non-Human noble population, though the Vargr have exceeded that number at times, and the Aslan, Bwaps, and Suerrat routinely approach it."
Let’s assume that any cosmopolitan world will have a sizable minority of non-humans. And by cosmopolitan I’m thinking just pop A, starport A mainworlds. Ignoring the T5SS data, let’s use some standard odds from worldgen to calculate numbers.
- There are about 10,000 worlds in the Imperium
- About 2.77% of those, or 277, will be Pop A worlds. (Collectively these 277 worlds would be almost 81% of the total population.)
- About 16.65% of those, or 46, will have Class A starports
- Assuming a pop multiplier of 5, that gives us about 2.3 trillion as the total Imperial Population on Pop A, Class A starport worlds.
Let’s assume just 10% of that population, or 231 billion, are non-humans on Pop A, Class A starport worlds across the Imperium. Collectively that’s huge, but because no one sophont species has a large percentage they wouldn't show up in the T5SS data.
If you take that 231 billion number and project some assumed percentages, you can see how large the missing populations would be:
- Vargr (assume 5% of non-humans) – 11.5 billion
- Bwap (assume 4% of non-humans) - 9.2 billion
- Aslan (assume 3% of non-humans) - 6.9 billion
- Suerrat (assume 3% of non-humans) - 6.9 billion
Again, that’s just on pop A, starport A worlds.