At level 2 or above the gap increased by 0.2 percentage points, at level 3 or above it decreased by 0.2 percentage points and at level 4 or above it increased by 0.3 percentage points.
Ar lefel 2 neu uwch, cynyddodd y bwlch 0.2 pwynt canran; ar lefel 3 neu uwch, lleihaodd 0.2 pwynt canran; ac ar lefel 4 neu uwch cynyddodd 0.3 pwynt canran.