All of the figure work I have done has been in workshop settings. In each instance, the models have been non-professional, sometimes students, and sometimes recruited through friends of the organizers. In looking back, I would say that perhaps 50% of then have been good to excellent, while the others have ranged from mediocre to horrible. Overall, the distribution pretty much followed a normal bell curve.
Several years ago I tried placing some announcements on strategically-located bulletin boards - post offices, bulletin boards in areas appealing to folks with alternative life styles, photo shops, etc. Didn't get a lot of responses. One was a photographer who had done figure work in college, enjoyed it, and wanted to do more after she got into the "real world". The other was from a guy who seemed to be fixated on size, and one phone conversation was as much contact as I cared to have with the dude. Different experience, but once again the conclusion is normal distribution.