No I don't have stats but here where there is a high immigrant population, the prostitutes and strippers coming in are working in those bars and nightclubs the immigrant men frequent. If you look in Mexico, prostitution is very open and common --- so it would be strange to think they gave it up just from crossing the border. Also it is often immigrant men who have left wives and girlfriends behind and have more "need" in using prostitutes. Just go to the border and look around --- see the patrons yourself. What goes on in the USA likely goes on in England --- and it's not likely that only the native born men are using the foreign prostitutes --- although a number of them also are.
A friend told me this... ;-)
Since neither of us can produce stats, I guess we'll have to let the readers decide who is or isn't contributing to these pimps by their patronage.