This meant that the sample was a third lower than previous surveys and it was not possible to analyse the survey results by local authority as had been done in the previous surveys.
Golygodd hyn fod y sampl draean yn is na’r arolygon blaenorol ac nid oedd modd dadansoddi canlyniadau’r arolwg yn ôl awdurdod lleol fel a wnaed yn yr arolygon blaenorol.