There Hasn't Been Net Undocumented Immigration From Mexico For Half A Decade

In 2012, 5.9 million unauthorized immigrants from Mexico lived in the U.S., down about 1 million from 2007. Despite the drop, Mexicans still make up a slight majority (52% in 2012) of unauthorized immigrants. At the same time, unauthorized immigration overall has leveled off in recent years. As a result, net migration from Mexico likely reached zero in 2010, and since then more Mexicans have left the U.S. than have arrived.

From the Pew Research Center via Marginal Revolution.