Within the social sector, there may be an overcount of Registered Social Landlord (RSL) builds and an undercount of local authority builds (see notes).
Efallai bod adeiladau Landlordiaid Cymdeithasol Cofrestredig (RSL) wedi eu gor-gyfrif ac adeiladau awdurdodau lleol wedi eu tan gyfrif (gweler y nodiadau).