That's what I had thought too, but there's no way there could have been 4,905 congressional appointments and 806 Presidential appointments.
I think 157 is the number that received the nomination, which is surprisingly low. JROTC as a recruitment program is apparently just not pulling very many candidates for the Academy.
Only JROTC units that are "Honor Units with Distinction" can nominate and there are really not that many battalions that are honor units with distinction.