Between 2017/18 and 2021/22 academic years, young people reporting that they did not smoke and that they never or rarely drank alcohol has shown slight improvements.
Rhwng blynyddoedd academaidd 2017/18 a 2021/22, mae nifer y bobl ifanc a ddywedodd nad oeddent yn ysmygu ac nad oeddent byth neu’n anaml yn yfed alcohol wedi gwella rhywfaint.