Your faulty numbers are caused by ignoring the fact that the illegal immigration numbers have spiked in the last couple of years.
The best estimates I've seen show 3 million or so coming in the last year alone.
By the way, I believe that the Bear Stearns number of 20 million plus is a conservative estimate.
After looking at the data and traveling the country extensively the last couple of years, seeing the deep penetration of the illegal population into heretofore uninvaded territory, my personal opinion is that the current number is actually over 30 million.
During the debate over the '86 amnesty, proponents claimed that the amnesty would be granted to about a million illegals. It ended up being three times that.
I think that the same math will hold true today if we are stupid enough to repeat the mistakes of the past.
""The best estimates I've seen show 3 million or so coming in the last year alone.""
Mexico's population would be falling if that were the case