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