The two charts above show how the time taken to repay higher rates refunds has changed over time, and the proportion of all refunds that are paid within both 30 and 60 days.
Mae'r ddau siart uchod yn dangos sut mae'r amser a gymerir i ad-dalu cyfraddau uwch wedi newid dros amser, a chyfran yr holl ad-daliadau sy'n cael eu talu o fewn 30 i 60 diwrnod.