While a number of European countries have reached birth rates low enough to be lower than replacement, the United States has in fact not done so. It is right around the replacement rate; adding in immigration, and we have a still-expanding population base.

My source for this analysis is a recent work called Common Wealth: Economics for a Crowded Planet by Jeffrey D. Sachs http://www.amazon.com/Common-Wealth-Economics-Crowded-Planet/dp/1594201277. Recommended reading.

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