The main source of data is the Wales National Workforce Reporting System (WNWRS) which has replaced the General Medical Services census as the main source for GP workforce statistics.
Prif ffynhonnell y data a ddefnyddir yw’r System Adrodd Genedlaethol y Gweithlu Cymru (WNWRS) sydd wedi'i gyflenwi a'i ddilysu gan Bartneriaeth Cydwasanaethau'r GIG.