Of the 73 countries who took part in the Programme for International Student assessment (PISA) in 2018 and 2022, all but ten saw a decline in at least one area this year.
Gwelodd pob un ond deg o'r 73 gwlad a gymerodd ran yn asesiadau rhyngwladol PISA yn 2018 a 2022 ostyngiad mewn o leiaf un maes eleni.