7 million persons, comprising approximately 12 percent of the United States population. Of this group, estimates indicate approximately 10.3 million ù 29 percent of the foreign born ù were unauthorized migrants" (Van Hook et al). As previously noted, the Pew Hispanic Center estimates that unauthorized migrants currently number 12 million. A federal government analysis of the 2000 census showed that the unauthorized population grew by roughly 500,000 a year from 1990 to 2000 (INS). If the Pew numbers are correct, this would mean that this growth has actually increased over the past six years. Additionally, it is important to note that this growth represents the net increase in the unauthorized population. Because somewhere between 200,000 and 300,000 unauthorized aliens leave the country, naturalize, or die in any given year, the gross increase in the unauthorized population is actually closer to 750,000 a year (Van Hook et al).
Some of these unauthorized aliens arrived legally into the United States either as tourists, students, or workers, and have overstayed their visas. The Department of Homeland Security has deployed a system known US-VISIT at all Ports of Entry (POE). All aliens presenting themselves for entry at a POE have two fingerprints and a photograph entered into the US-VISIT system. However, the system has yet to be expanded to include aliens leaving the country (DHS). This means that o