These numbers seem really hard to believe, but perhaps I'm out of touch.
jj1000 is fire against what i'm about to say, but i'll say it anyways. Many times when a person specializes in a problem, being that he deals with it so much, they overestimate how prevalent the problem is, it's human nature. Now if the problem is heart problems, there are scientific studies how prevalent that is, and he won't overestimate. Or if the problem is blindness, you walk in the streets and see that most ppl aren't blind. But a problem with no studies and that's hidden, I think it's human nature to overestimate.