Is getting thinner:

It's an open secret in the porn world that many female performers are supplementing their income by "hooking on the side". It's also called "doing privates", as in private bookings. The official industry line is that it's dangerous (because clients aren't tested the way performers are) and irresponsible (because the women could then infect the closed community of professional performers). But the women can make far more money having sex behind closed doors than doing it on film and, in fact, the practice is widespread. For many female performers nowadays, the movies are merely a sideline, a kind of advertising for their real business of prostitution.

Recent Dish on the collapse of the porn industry here.