I also find the data highly questionable--it's very popular to pretend that prostitution is "trafficking" with little or zero evidence. I recall a news article recently about a bunch of "trafficking" busts--that was the police putting up ads and busting the guys who showed up. Trafficking women requires that there be women in the first place and there were none.

And, no, women who move around a lot and live on-site isn't proof of trafficking--because that's also a way to make it much harder for the cops to investigate and thus a sensible safety strategy for them. I'm sure trafficking exists but I don't believe the claimed numbers at all.