There are 55.3 million Latinos in America, nearly triple the 1980 population, and those under 18 years old are the largest group, a demographic fact likely to influence the future of the country, according to Census figures. The new report helps to complete the picture of the U.S. immigration population, which previous reports pegged at 61 million. According to Pew, 35.3 million, or 64 percent of the total number of the Latino immigrant population are Mexican-origin. A 2008 Pew report said that more than half of the immigrants from Mexico were illegally in the United States.