This also continued a longer-term upward trend, with the latest data 2 percentage point higher than in the previous year, and 13 percentage points higher than in 2016.
Mae hyn yn gynnydd o ddau bwynt canran o'r flwyddyn flaenorol, a chynnydd o 11 pwynt canran o 2016 (blwyddyn gyntaf data cymaradwy).