Residential revenues then increased, with monthly revenues in September to December 2021 being the highest seen to date, except for the June 2021 peak.
Yna cynyddodd refeniw preswyl, gyda refeniw misol o fis Medi i fis Rhagfyr 2021 yr uchaf a welwyd hyd yn hyn, ac eithrio brig Mehefin 2021.