The overall Wales totals are estimated from the survey results by assuming that the increase from last year for the population as a whole is the same as that we see in the sample.
Amcangyfrifir cyfansymiau cyffredinol Cymru o ganlyniadau’r arolwg drwy dybio bod y cynnydd o’r llynedd ar gyfer y boblogaeth gyfan yr un fath â’r hyn a welwn yn y sampl.