Really?

I was watching a debate on reservations on CNN IBN, on the day the resident doctors called off the strike, when a pro-quota panelist said that just about 25 per cent Indians fell in the `other castes’ category while the remaining 75 per cent comprised SC/STs and OBCs and so it was valid to give them 50 per cent reservation.
Really? Could anyone please enlighten me on this? Had no idea that the backward classes constituted the country’s majority.