The data presented covers 16 to 18 year olds and 19 to 24 year olds on an academic age basis (age as at 31 August prior to the start of the academic year).
Mae'r data a gyflwynir yn cwmpasu pobl 16 i 18 oed a 19 i 24 oed ar sail oedran academaidd (oedran ar 31 Awst cyn dechrau'r flwyddyn academaidd).