The Department of Homeland Security says 11.6 million illegal aliens lived in the United States as of January 2006 — 1.1 million more than the estimate for January 2005.

In a report released yesterday, DHS also said Mexico accounted for about 6.6 million of the total illegal aliens, and accounted for three-fifths of the annual increase in illegal aliens in the past six years.

The estimates are the latest official government attempt to calculate the illegal population, derived from the U.S. Census Bureau's 2005 American Community Survey and calculations about the number of illegal aliens as part of the foreign-born population.

Officials said the jump of 1.1 million doesn't necessarily mean that many new illegal aliens came to stay in 2005, but reflects better numbers and suggests the January 2005 estimate of 10.5 million was too low.

The government estimates that in 2000 there were 8.5 million illegal aliens, suggesting an annual net increase of about 500,000 per year since then