Children and young people aged 0 to 15 years old accounted for the remaining 17.6% of the population in mid-2021 (547,000 children and young people).
Plant a phobl ifanc 0 i 15 oed oedd yn cyfrif am y 17.6% arall o'r boblogaeth oedd yn weddill yng nghanol 2021 (547,000 o blant a phobl ifanc).