This was the point I was trying to make when we last discussed this topic, before the thread ("Should Prostitution be Legalised") descended into a slagging match.
Hence the "not bothering to go over the same arguments again and again" thing.
The question of whether or not society can abdicate responsibility for the social, financial or medical well-being of an individual, on the grounds that their freedom to act as they will might otherwise be compromised, is going to take a lot more answering than any random statistics can provide.
Not that I disagree entirely with the pro-decriminalisation arguments, but I haven't seen any sufficiently convincing reasoning yet.