Bethelites would be high also. Initially, most called are 19 yrs old males, and raised in. Now moving away from home, often controlling JW parents, they have to grow up and many now get a chance to think on their own, without Mom & Dad influence. Also, they get the insider experience of the "control" and leadership demands and contradictions and 'no love' reality.
Back in '71 or so, at Bethel, word was that most were not completing their 4-yr vow anyway and not just leaving Bethel but the whole works (Organization.) Not sure when, but Bethel dropped their 4-year sign-up down to one year requirement.
Auxillary Pioneers, signup has been dropping dramatically also in recent years, thus the 'bar" dropped to 30 hr. requirement.