Aneurin Bevan health board saw the highest proportion spending less than 4 hours in emergency departments (77.0%), and Cwm Taf Morgannwg saw the lowest (67.7%).
Bwrdd iechyd Aneurin Bevan 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 (64.7%).