The impacts of UPC and of revisions to migration will not total the overall change to the population because of the exclusion of births, deaths and special changes to the population.
Gall newidiadau dros amser i godau galwedigaethau’r GIG a’r codau newydd a roddir i staff effeithio ar ffigurau yn ôl grŵp staff, ond nid effeithir ar y niferoedd cyffredinol.