Yes, I'd like to point to an RCMP report on human trafficking. Although I don't have specific numbers, there are studies about the money that's involved in human trafficking into prostitution, but it's an illicit activity so it's difficult to pin down those numbers. The most accurate ones are probably from police, and we can glean some of the understanding of how much money is at stake by looking at regimes where they've legalized and what the revenue flows are there.
The RCMP looked at human trafficking in Canada, and they saw that human trafficking and prostitution proliferate in cities where there's a large enough Asian population that organized crime will operate there. The massage parlours are a network across Canada that is obviously controlled by organized crime, and they don't do things for fun; they do things for profit.