According to the 2000 Census, Pima County, Arizona has a population of 843,746 people. Of those, 633,387 (75%) are White, 25,594 (3%) are Black, and 247,578 (29%) are Latino. However, 6,916 (or 1% of the 843,746 people) are not residents by choice but are people in prison.
Even though prisoners cannot participate in the local community, the Census Bureau nevertheless counts them as residents of the county where they are incarcerated.
A more accurate description would not include the prisoners. This would give Pima County a population of 836,830 with a demographic that is 75% White, 3% Black, and 29% Latino.
The numbers for Whites, Blacks and Latinos may not add up to the total number because we have not included racial groups other than Whites and Blacks and because the Census Bureau considers "Latino" to be an ethnicity, not a race. Most of the people reported as being Latino are also counted as being White or Black.