Different timelines it seems. Although don't know how much that depends on how far out from other universes you are. I know there are some people that are here from the 1800-1900 turn of the century while my universe is more the 2020s brand.
So, geek out! Says the self proclaimed geek.
The roster varies. People come and people go, so an accurate count at any given time is questionable. And so far, I think it's still split. we haven't gotten everyone out of the simulation yet. Attempts are being made, but the recoop makes available people unreliable.