The start of the new survey in 2020 was delayed by COVID-19, but data collection took place from July to December 2020.
Cafodd y gwaith o gasglu'r data hwn ei atal ar ddechrau pandemig y coronafeirws (COVID-19) ym mis Mawrth 2020 ac nid oes data ar gael ar gyfer blynyddoedd ysgol 2019/20, 2020/21 a 2021/22.