The main source of data is the Wales National Workforce Reporting System (WNWRS) and information on data collection processes and statistical quality is available in the quality report.
Prif ffynhonnell y data yw System Adrodd Genedlaethol y Gweithlu Cymru (WNWRS) ac mae gwybodaeth am brosesau casglu data ac ansawdd ystadegol ar gael yn yr adroddiad ansawdd.