The states with the highest percentages of people of African descent are Mississippi (36%), and Louisiana (33%). While not a state, the population of the District of Columbia is more than 50% black. Recent African immigrants represent a minority of black people nationwide. The U.S. Bureau of the Census categorizes the population by race based on self-identification. The census surveys have no provision for a "multiracial" or "biracial" self-identity, but since 2000, respondents may check off more than one box and claim multiple ethnicity that way.