DC has a 50% black population. This may explain a lot also.
District Of Columbia High Schools
12,521 Black - (88%)
962 Hispanic - (7%)
519 White - (4%)
201 Other - (1%)
32 High Schools
14,203 Students
1,311 Full-time Teachers
10.8 Student-Teacher Ratio
http://publicschoolsk12.com/high-schools/dc/