In Wales the gap widened by 1.7 percentage points and in the UK, it has widened by 0.6 percentage points compared to the previous year.
Yng Nghymru ehangodd y bwlch 1.7 pwynt canran ac yn y DU ehangodd 0.6 pwynt canran o'i gymharu â'r flwyddyn flaenorol.