Values were only calculated within each group if there were at least 10 other businesses who had provided exact values in the same group as the record requiring imputation.
Dim ond os oedd o leiaf deg busnes arall wedi darparu union werthoedd yn yr un grŵp â'r cofnod yr oedd angen ei briodoli y cyfrifwyd gwerthoedd o fewn pob grŵp.