I am not really sure how to answer your question but I will try. Most born in Baptists usually leave over one or 2 things, usually it involves alcohol and partying. These kids want to leave home and party and drink---and they usually come back later on after they are all partied out. Many also tend to find other churches that are more stiff in their worship style--the kind where everything is planned out, and nothing is impromptu.
It seems like most JW's leave for so many varied reasons, too numerous to name!
Statistic wise, I can't say who has the greater number of born ins who leave vs. the amount that eventually return.