Data are extracted on 31 March, 30 June, 30 September and 31 December each year by NHS Wales Shared Services Partnership (NWSSP).
Caiff data eu hechdynnu ar 31 Mawrth, 30 Mehefin, 30 Medi a 31 Rhagfyr bob blwyddyn gan Bartneriaeth Cydwasanaethau GIG Cymru (NWSSP).