Aneurin Bevan health board saw the highest proportion spending less than 4 hours in emergency departments (76.2%), and Cwm Taf Morgannwg saw the lowest (64.7%).
Bwrdd iechyd Bae Abertawe welodd y gyfran uchaf yn treulio llai na 4 awr mewn adrannau achosion brys (76.2%), ac yng Nghwm Taf Morgannwg oedd y gyfran isaf (61.4%).