Among the 50.7 million Hispanics in the United States, nearly two-thirds (65%), or 33 million, self-identify as being of Mexican origin, according to tabulations of the 2010 American Community Survey (ACS) by the Pew Hispanic Center, a project of the Pew Research Center. No other Hispanic subgroup rivals the size of the Mexican-origin population. Puerto Ricans, the nation’s second largest Hispanic origin group, make up just 9% of the total Hispanic population in the 50 states and the District of Columbia.