Estimates on the new basis are only available from 2008 onwards and figures within this release are therefore not directly comparable with those on the basis of the previously used definition.
Mae amcangyfrifon ar y sail newydd hon ond ar gael o 2008 ymlaen, ac felly ni ellir cymharu'r ffigurau yn y datganiad hwn yn uniongyrchol â'r ffigurau sy'n seiliedig ar y diffiniad blaenorol.