The questions in the 2017-18 National Survey for Wales on Active Travel differ to previous questions and therefore data are not directly comparable with previous statistical bulletins.
Ar gyfer y dadansoddiad hwn, cafodd data o'r Rhestr Cleifion a Warchodir eu cysylltu â data o Arolwg Cenedlaethol Cymru 2018-19 (2017-18 ar gyfer y cwestiynau ar unigrwydd).