"This report presents estimates of the legal permanent resident (LPR) population living in the United States on January 1, 2007. The LPR population includes persons granted lawful permanent residence, e.g. 'green card' recipients, but not those who had become U.S. citizens. The estimates are shown for the total LPR population and the LPR population eligible to apply to naturalize by country of birth, state of residence, and the year LPR status was obtained. Data for the estimates were obtained primarily from administrative records of U.S. Citizenship and Immigration Services (USCIS) of the Department of Homeland Security (DHS). The methodology used for the 2007 estimates is similar to that used in previous DHS estimates (see Rytina, 2006 and 2008). Minor changes in assumptions, made to be consistent with DHS estimates of the unauthorized population, had little effect on the estimates. In summary, an estimated 12.8 million LPRs lived in the United States on January 1, 2007. Nearly 48 percent obtained LPR status in 2000 or later."
United States Department of Homeland Security: http://www.dhs.gov/