At least 23% of those who agreed to complete, went on to do so (this is likely an underestimation due to difficulties recording this.
Aeth o leiaf 23% o'r rhai a gytunodd i’w gwblhau ymlaen i wneud hynny (mae hyn yn debygol o fod yn amcangyfrif rhy isel oherwydd anawsterau cofnodi hyn).