Immigrants Maintain Population Levels Of Major U.S. Cities

LOS ANGELES - APRIL 5: Pedestrians shop in an old section of Chinatown April 5, 2007 in Los Angeles, California. As the demographics of large cities in the U.S. continue to shift, populations of large U.S. cities would shrink without immigrants who provide the only source of growth as native-born Americans move to other regions, according to Census Bureau estimates released this week. Without the influx of immigrants from 2000 to 2006, the New York metro region would have lost an estimated nearly 600,000 people while the Los Angeles area would have lost more than 200,000, San Francisco down by 188,000 and Boston 101,000 people. The U.S. has about 36 million immigrants, a third of whom are in the country illegally. Many people believe that a shrinking population would hurt the U.S. economy. (Photo by David McNew/Getty Images)