According to the 2000 Census, San Juan Municipio, Puerto Rico has a population of 434,374 people. Of those, 315,939 (73%) are White, 51,572 (12%) are Black, and 425,652 (98%) are Latino. However, 3,170 (or 1% of the 434,374 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 San Juan Municipio a population of 431,204 with a demographic that is 73% White, 12% Black, and 98% 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.