The last official figure I heard was in 2005 and that 1240 approx across all ranks.
We were undermanned at the time and the reason given as to why there was no problem is because the RMP gets the numbers in the careers office so the powers that be dont see a problem because the recruiting statistics are showing a perfect score.
Sadly, for reasons too numerous to get into a discussion about here the retention in the RMP is shocking but the powers dont seem to look at that end.
RMP mostly get out of the Army with pipe dreams that they are going to walk into a job in civvy bill, to be fair a lot do make it into civvy bill but its not as easy as they expect.
Others just decide its not for them.
Recently I've noticed a trend that many are transferring to other capbadges.
The fact is that the RMP treat its people like shite, the hours are long and the work is demanding and there is always some ponce sat in an ivory tower barking deadlines at you.
I for one love it, but that is because I dont care about the ponce in the ivory tower he can give me as many ridiculous demands and deadlines as he wants. I'll put them onto my huge 'to do' pile and get around to them when I get there.