http://www.theglobalist.com/StoryId.aspx?StoryId=5759
Here's an interesting article. I don't know anything about the website, was just looking for some statistics.
The US population in 1776 was 2.5 million.
Elsewhere in the article it says there's going to be another 140 million people let in by 2050.
At one time our open society needed more people, now I don't know how our country can survive with all these barbarians at the gates.