Though the number of undocumented immigrants living in the U.S. appears to have leveled off, the population is more widely disbursed and the number of children born in the U.S. to unauthorized immigrant parents has increased dramatically, according to a report released Tuesday by the Pew Hispanic Center.

In Utah, the number of undocumented residents is estimated at 110,000 — up about 15,000 from 2005.

University of Utah research economist Pam Perlich said Tuesday that the report provides a detailed picture of undocumented immigrants in the U.S., who number about 11.9 million and comprise 4 percent of the nation's population and 5.4 percent of the workforce.

In Utah, those numbers come in at 4.1 percent of the population and 5.8 percent of the workforce.

Perlich said Utah is one state that has felt the effects of the redistribution noted in the report.

"The undocumented population continues to grow in Utah by people rearranging themselves within the country," Perlich said. "The state has a great reputation, a great quality of life and is known as being very family-oriented."

The report cites an explosion in the number of U.S.-born children in "mixed status" families (undocumented immigrant parents and citizen children) from 2.7 million in 2003 to 4 million in 2008. Perlich said this phenomenon is also present in Utah, and she estimated that about one-third of all pre-schoolers in Salt Lake County are the progeny of immigrant parents.

While this growth has been a much-debated political issue, Perlich said that as baby-boomers move into retirement, more people than ever before are relying on federal retirement benefits such as Social Security and Medicare, and the upcoming generation, of which these immigrant children are a part, will be subsidizing those retirees.

"The success of these children is something we should be investing in right now," Perlich said. "We've got to get more educated as a nation … and the one investment my generation can make is to ensure the best possible education for these kids."

The report said that children of undocumented immigrant parents lag far behind their native-born counterparts in educational attainment, with 47 percent of those aged 25-64 having less than a high-school education, compared with only 8 percent of U.S. born citizens who lack a high-school diploma.

Among undocumented immigrants, a third of the children and a fifth of the adults also are living below the poverty line – nearly double the rate for native born children (18 percent) and adults (10 percent.)