One in every 11 people born in Mexico and still alive is a U.S. resident, and about half of these immigrants crossed the border illegally, according to a comprehensive report released Tuesday. In the Pew Hispanic Center study of immigration trends, analysts estimated that in March 2004 about 10.3 million immigrants from around the world were living in the United States without legal documents to be here -- some 24 percent of them in California. About 10.6 million people born in Mexico live in the U.S. -- about 5.9 million of them illegally. "This (study) shows that not only are they not going home, but more are coming. "If we are going to realistically deal with this population, we have to figure out what to do with the people who are staying." Most undocumented immigrants are Mexicans with little education. And though they make incremental strides, many never achieve economic success, with about 27 percent lingering in poverty -- twice the rate for native-born Americans. The study, prepared for a bipartisan independent task force on immigration, comes as Congress faces increased pressure to revamp what some have called a broken system.