There was little variation between the health boards, with only 1 percentage point difference between the highest rate (Cwm Taf Morgannwg) and the lowest rate (Cardiff and Vale).
Nid oedd fawr ddim amrywiaeth ymhlith y byrddau iechyd, gyda gwahaniaeth o 1 pwynt canran yn unig rhwng y gyfradd uchaf (Cwm Taf Morgannwg) a’r gyfradd isaf (Caerdydd a’r Fro).