The value for April 2019 to March 2020 will have already been subject to some of this downward revision, whereas the equivalent figure for April 2020 to March 2021 will not have been revised so much.
Bydd gwerth Ebrill 2019 i Fawrth 2020 eisoes wedi bod yn destun rhywfaint o ddiwygio am i lawr, ond nid yw’r ffigur cyfatebol ar gyfer Ebrill 2020 i Fawrth 2021 wedi cael ei ddywygio cymaint.