chopping rate varies.
I've seen batches with 60% chopped. But there are those high quality ones where 100% make it.
don't bother abt chopping, if u can, u can.
But even when qualified as FO, you may not be spared the chop, SQ6 is one eg, plus there are those who fail their medical or base check, then same thing, out u go..., even if u are captain.
There are even cases where cadets got chopped during OBS, ie not even training yet. eg, if u show signs of seasickness during sailing at OBS, good luck.