I dunno man I think it's more like 25% of people leaving with an EP....The big question is the disparity between us and the water wing guys- something is not translating: how is it that #1 squadron aviators are being looked over, but basically any SWO and submariner breathing and with a pulse got picked up?
Maybe I'm way off, but I specifically remember a thread on here a while ago re: administrative screening for aviators (either DH or CO, I forget). The stats showed that like the majority of guys had an EP coming into the board; I'll try to find it... At my current job, I'm ranked against aviators and I've noticed they put a lot of effort into reporting and transferring at opportune times to maxinize EPs amongst themselves. I can only speak for SWOs, but this mentality just doesn't exist, if you're not a top level guy, no one is going out of their way to hook you up with an EP.
Your bolded question cuts to the heart of it, and it's the question you should asking your community flags and PERS guys. Is it because all 11XX guys are already DHs? Was there a precept for this board saying to look at Masters and JPME (something 11XX have more time built in to their career path to complete prior to O4)? Either way, I agree with you that it's totally inequitable if there are aviators that have winning records who are being left on the table just because a mid-pack SWO is already in his DH ride.