According to the 2000 Census, Mercer County, Pennsylvania has a population of 120,293 people. Of those, 112,031 (93%) are White, 6,318 (5%) are Black, and 803 (1%) are Latino. However, 1,051 (or 1% of the 120,293 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 Mercer County a population of 119,242 with a demographic that is 93% White, 5% Black, and 1% 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.