In the 2000 Census, it was possible for the first time for enumerees to check two or more boxes in response to the "race" question. These maps count only those who checked a single box with any given "race." That is, a category like "Non-Hispanic White" really means "Non-Hispanic White only." The new categorization of "race" in Census 2000 might suggest that it is impossible to compare the 1990 and the 2000 Censuses at all, but, since only ca. 3% of the respondents in the Chicago area considered themselves "multiracial," the effect of the change is probably fairly minor. People who reported being "multiracial" are disproportionately located on the North and Northwest Sides of the City of Chicago and in adjacent suburbs.