"In 2010, there were 50.5 million Hispanics in the United States, composing 16 percent of the total population .... Between 2000 and 2010, the Hispanic population grew by 43 percent—rising from 35.3 million in 2000, when this group made up 13 percent of the total population.9 The Hispanic population increased by 15.2 million between 2000 and 2010, accounting for over half of the 27.3 million increase in the total population of the United States."
According to the 2010 Census, "'Hispanic or Latino' refers to a person of Cuban, Mexican, Puerto Rican, South or Central American, or other Spanish culture or origin regardless of race."

Source

Humes, Karen R.; Jones, Nicholas A; & Ramirez, Roberto R., "Overview of Race and Hispanic Origin: 2010," U.S. Census Bureau (Washington, DC: U.S. Department of Commerce, Economics and Statistics Administration, May 2010), p. 3.
http://www.census.gov/prod/ce…