The question isn't really population. It's scarcity of resources. If you look at a population density map of the US, there's a whole lot of nothing in the middle of the country.
As far as sterilization policies, see Ehrlich, Paul.
Edit: the rate of growth is decreasing. Where does that fit into your calculations?
Edited 1 time(s). Last edit at 12-Feb-19 23:43 by Aine.