Thread:Ghelæ/@comment-5080468-20170729213650/@comment-47205-20170730134600

That's still far more on the social science side of things than where most of my knowledge lies... but anyway. If we assume that the only/majority population of colonised/annexed systems are the recent colonists, then within 20 years that population might not have grown much: for several years after starting a new colony, you might expect the colonists would be too busy setting up their new home to be looking after children. So the new inhabitants born on new colonies within the last 20 years might be a small enough contribution to the overall population that their effect is far less than the errors from the rest of any approximation.

So then let's say we're looking at around 1600 systems where the population came from. It comes down entirely to making a guess as to the average population of a system. I'd suggest it's somewhere between 100 million and 1 billion, then the total population would be somewhere between 160 billion and 1.6 trillion.