Six housing associations, two of which were the Large Scale Voluntary Transfer bodies which took over the ownership of former council housing, did not submit returns.
Ni chafodd ffurflenni eu cyflwyno gan chwe chymdeithas dai, yr oedd dwy ohonynt yn gyrff Trosglwyddo Gwirfoddol ar Raddfa Fawr a ddaeth yn berchnogion ar dai cyngor blaenorol.