That's the ratio New York City was getting until they started digging a little deeper, at which point the hetero infection rate dropped down to near zero. Of course, investigating the "hetero" rate became politically unpopular, so they stopped.
Doctor: "Are you a homosexual Mr. Smith?"
Smith: "Why, no, doctor!"
Doctor: "Of course you're not..."
"That's the ratio New York City was getting until..."
Source please? (fully expecting no reply)