These data are taken from the Annual Survey of Hours and Earnings (ASHE), which is run by the Office for National Statistics (ONS) and are published as National Statistics.
Daw’r data hyn o’r Arolwg Blynyddol o Oriau ac Enillion, sy’n cael ei redeg gan y Swyddfa Ystadegau Gwladol ac sy’n cael ei gyhoeddi fel Ystadegau Gwladol.