"In the 2010 Census, 97 percent of all respondents (299.7 million) reported only one race (see Table 1).10 The largest group reported White alone (223.6 million), accounting for 72 percent of all people living in the United States.11 The Black or African-American alone population was 38.9 million and represented 13 percent of the total population.12 There were 2.9 million respondents who indicated American Indian and Alaska Native alone (0.9 percent). Approximately 14.7 million (about 5 percent of all respondents) identified their race as Asian alone."

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. 4.
http://www.census.gov/prod/ce…