According to Department of Homeland Security statistics, there were an estimated 460,000 unauthorized immigrants in Arizona in January 2009. That statistic, making Arizona the state with the seventh largest illegal immigrant population, was often cited last week, as Gov. Jan Brewer signed the nation’s toughest law on illegal immigration.

The number comes from “Estimates of the Unauthorized Immigrant Population Residing in the United States,” a report that the DHS releases each year, but sadly does not add to Data.gov. It takes a little digging to find it, but the most recent report for January 2009 (released in ...