There were 4,100 staff present, up from 3,900 in the previous week and 3,400 in the week before the Whitsun school holidays.
Roedd 3,900 o staff yn bresennol, i fyny o 3,700 yr wythnos flaenorol a’r 3,400 yn yr wythnos cyn y gwyliau ysgol Sulgwyn.