All stages in the collection, validation and production of these statistics are led by professional statisticians working for the contractor and statisticians from the Government Statistical Group.
Cefnogir pob cam wrth gasglu, dilysu a chynhyrchu'r ystadegau hyn gan ystadegwyr proffesiynol sy'n gweithio i'r contractwr a'r ystadegwyr o Grŵp Ystadegol y Llywodraeth.