[Note 1] Data has been revised for the years 2021-22, 2020-21 and 2019-20 since previously published.
[Nodyn 2] Mae data wedi'u diwygio ar gyfer y blynyddoedd 2021-22, 2020-21, 2019-20 a 2015-16 ers eu cyhoeddi'n flaenorol.