Given that whites outnumber blacks by 7:1 or more, the fact that the number of new HIV cases among blacks is nearly the same as that of white is significant. Black MSMs get HIV at much higher rates than whites.
The heterosexual women numbers are interesting as well, perhaps more so. It would seem to likely imply that a lot of black MSM are also hitting on the women.
google “down low”.
An article in the Chicago Reader, a few years ago, addressed this statistic.
A "gay-friendly" organization sent undercover reporters into gay bath houses to observe and note the occurrence of unprotected sex.
What they reported was this: Black and Hispanic men had unprotected sex at a significantly higher rate than Caucasian men. This was at a time when various organizations had begun a major initiative to influence homosexual men to use condoms.
That's reason #1.
Reason #2 is mentioned above by another FReeper: "Down Low".
Reason #3 is IDU - Intravenous Drug Users.
Reason #4 is the typically-African desire for "dry sex"
Feel free to add any other reasons.