yes, since each time your pop grows, is grows by more % than it did last time, so you would have:
1 pop - 10 citizens
2 pop - 25 citizens
3 pop - 48 citizens
4 pop - 90 citizens
5 pop - 150 citizens
Get what I mean?
Perfect, that's exactly what I wanted to know, thanks. That's useful to know for this scenario, in particular. Someone in the main forum also tipped me off to the fact that you can check your actual population by scrolling over the bar at the top of the city screen (which I guess I never saw a reason to do before

I'm also attaching a save of the game I'm talking about. If someone can clear up my confusion, then you will have my eternal gratitude (at least, as close to eternal as I can get).
If you're wondering about all the MAs and destroyers---when I went back to the autosave to test, I dropped a bunch around to make contact with everybody, then filled my cities with embassies (also gave myself a bunch of random techs out of frustration

It was a pretty fun game---you'll see that I got over China in pop (according to the F8 screen) by invading Persia and was about to make 1200AD just as my economy tanked completely.
EDIT: thanks also for your reply deanej!