The survey response rate was 47%, i.e. of all Welsh speakers identified in the National Survey for Wales, 47% of those had completed and returned the questionnaire.
Cyfradd ymateb unigolion yw nifer y preswylwyr arferol y cafodd manylion unigol eu darparu ar eu cyfer ar holiadur a ddychwelwyd, wedi'i rannu ag amcangyfrif o'r boblogaeth breswyl arferol.