29% of mothers aged 19 or younger were smokers compared to less than 10% in each age group from 30 to 34 or older.
Roedd 29% o fenywod 19 oed neu ieuengach yn smygwyr o’i gymharu â llai na 10% ym mhob grŵp oedran o 30 i 34 neu hŷn.