It's less than that for AD boards, even less for civi boards. The selection rate for those who don't apply because they are too worried about selection rates is 0.000%
Cant remember the exact number but I think there were 44 selects and 200+ non selects from the May board. I was one of the lucky few. It does seem that the number is less and less each board though.
I'm going to preface this by reminding you that 75.6% of all percentages are made up on the spot. I have had heard this from multiple sources so there might be some credibility to it.
7/10 that start the application process get rejected because of medical reasons. Of the 3 that clear medical 1 gets selected.