Provisional figures are produced on a quarterly basis and are finalised along with the publication of Q4 data in February/March each year.
Cynhyrchir ffigurau dros dro bob chwarter, a bydd y ffigurau terfynol gan gynnwys data ar gyfer Ch4 yn cael eu cyhoeddi ym mis Chwefror/Mawrth bob blwyddyn.