WASHINGTON, March 21 (Xinhuanet) -- The undocumented immigrant population in the United States reached 10.3 million last year, a 23 percent increase over a four-year period ending March 2004, a report released on Monday showed.

    The rise in the undocumented population in the United States represented a net increase of about 485,000 per year between 2000 and 2004, according to the study by a private research group, the Pew Hispanic Center.

    About 5.9 million of the undocumented migrants are Mexicans, accounting for about 57 percent of the total, while 2.5 million others, or 24 percent, are from other Latin American countries.

    Most of the undocumented migrants have come to the United States to seek better job opportunities than in their native countries, according to the report. Enditem