the first united states census in 1790 classed residents as "free white" people (divided by age and sex), "all other free persons" (reported by sex and color), and "slaves". the 2000 census officially recognized six racial categories including people of two or more races; a category called "some other race" was also used in the census and other surveys, but is not official. in the 2000 census and subsequent census bureau surveys, americans self-described as belonging to these racial groups: