The continued designation of these statistics as National Statistics was confirmed in March 2010 following a compliance check by the Office for Statistics Regulation.
Cadarnhawyd bod yr ystadegau hyn wedi cadw eu statws fel Ystadegau Gwladol ym mis Mawrth 2010 yn dilyn archwiliad gan y Swyddfa Rheoleiddio Ystadegau.