As noted above, in 2016-17 several surveys previously run separately by the Welsh Government and three Welsh Government Sponsored Bodies were brought into one survey.
Fel y nodwyd uchod, yn 2016-17 daeth arolygon a oedd yn flaenorol yn cael eu rhedeg ar wahân gan Lywodraeth Cymru a thri Chorff a Noddir gan Lywodraeth Cymru ynghyd i ffurfio un arolwg.