Illegal Immigration: The population of Mexico is growing fast — too fast for its sluggish economy to sop up all the new workers entering the labor force. Not surprisingly, many want to come to the U.S. Of the 12 million people who have come to the U.S. illegally, most are from Mexico. Don't expect that number to shrink soon. New and alarming data gathered by the Pew Hispanic Center suggest it's likely to grow. A Pew poll of Mexican citizens found 46% would like to live in the U.S. — now. A fifth of them say they'd do so illegally....