The bar and line chart shows that for data by quarter the transaction was effective, the number and value of higher rates refunds claimed has varied considerably.
Mae'r siart bar a llinell yn dangos, ar y gyfer data fesul chwarter daeth trafodiadau i rym, bod nifer a gwerth yr ad-daliadau cyfraddau uwch a hawliwyd wedi amrywio'n sylweddol.