Average race-specific STD rates (number per 100 000 residents), 1999–2001 for six “race-income” county groups
| County group | Description of race-specific household income in county group | Chlamydia | Gonorrhoea | P &S syphilis | |||
| Black | White | Black | White | Black | White | ||
| 1 | Black and white incomes below national median | 695.2 | 88.8 | 597.0 | 22.9 | 10.7 | 0.5 |
| 2 | Black income below national median, white income above national median | 691.1 | 67.5 | 625.3 | 23.5 | 14.0 | 0.7 |
| 3 | Black income above national median, white income below national median | 279.3 | 61.3 | 125.4 | 5.6 | 6.2 | 0.1 |
| 4 | Black and white incomes above national median | 220.6 | 29.2 | 176.1 | 6.3 | 4.2 | 0.3 |
| 5 | No black households in county; white income below national median | – | 55.3 | – | 3.0 | – | 0.2 |
| 6 | No black households in county; white income above national median | – | 55.1 | – | 3.8 | – | 0.0 |