http://www.sfgate.com/cgi-bin/article.c ... IVNAF1.DTL

The current migration of Mexicans and Central Americans to the United States is one of the largest diasporas in modern history, experts say.

Roughly 10 percent of Mexico's population of about 107 million is now living in the United States, estimates show. About 15 percent of Mexico's labor force is working in the United States. One in every 7 Mexican workers migrates to the United States.
Migration is profoundly altering Mexico and Central America. Entire rural communities are nearly bereft of working-age men. The town of Tendeparacua, in the Mexican state of Michoacan, had 6,000 residents in 1985, and now has 600, according to news reports. In five Mexican states, the money migrants send home exceeds locally generated income, one study found.

Last year, Mexico received a record $20 billion in remittances from migrant workers. That is equal to Mexico's 2004 income from oil exports and dwarfing tourism revenue.