However, as the Annual Population Survey (APS) provides quarterly results, it is useful to use the APS to look at trends in the Welsh language between censuses.
Ond gan fod yr Arolwg Blynyddol o’r Boblogaeth yn darparu canlyniadau bob chwarter, mae’n ddefnyddiol er mwyn edrych ar dueddiadau’r Gymraeg rhwng cyfrifiadau.