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 Accredited Official Statistics.
Daw’r data hyn o’r Arolwg Blynyddol o Oriau ac Enillion, sy’n cael ei redeg gan y Swyddfa Ystadegau Gwladol (SYG), ac maent yn cael eu cyhoeddi fel Ystadegau Swyddogol Achrededig.