Data are collected by financial year and are subject to validation checks performed by Welsh Government statisticians and queries referred to local health boards where necessary prior to publication.
Mae'r ffigurau'n destun profion dilysu wedi'u rhagddiffinio trylwyr, a hynny o fewn y ffurflen ei hun, wrth i'r ffurflen gael ei chwblhau gan yr awdurdod, ac hefyd gan Lywodraeth Cymru.