Why did the US went from 3% to 2% growth? My guess is that before it had a very low population density and a lot of fertile land. That changed when population

Why did the US went from 3% to 2% growth? My guess is that before it had a very low population density and a lot of fertile land. That changed when population density increased. Check the conclusions of this article. http://mises.org/daily/1568 http://mises.org/daily/1568