While the white and Asian populations for San Francisco County continue to rise, there are fewer African-Americans here than there were in 2000, according to the U.S. Census Bureau. Ten years ago, there were 60,515 blacks living in the county; that number has decreased to just 51,850. This exodus doesn’t come as a surprise. As the city discovered in 2007, the median income for blacks was half that of whites, while the arrest rate was twice that of all others combined. Meanwhile, Asians now make up almost a third of the population in the county with 250,146 people. The figure is fully one-third in the city alone. Whites increased from 385,728 to 429,829. Here’s the most interesting statistic from the census, as reported by Blanca Torres of the San Francisco Business Times: The county has the highest percentage of vacant homes in the Bay Area, more than 30,000 of them.