Measuring the illegal immigrant population from 2000 through 2009, however, the department found an overall, 27-percent increase. About 62 percent of the undocumented in the United States last year were Mexican.
Between 2007 and 2009, the number of illegal immigrants in the country decreased by a cool million, "coincident with the U.S. economic downturn," according to the DHS report.
Besides Mexico, the top source countries for undocumented immigrants in 2009 were El Salvador (530,000), Guatemala (480,000), Honduras (320,000), and the Philippines (270,000). India, Korea and China also made the top-ten list of source countries.
California remained the state with the largest undocumented population, with 2.6 million illegal immigrants calling the Golden State their new home.