People with qualifications at or above National Qualification Level 4 were also more likely to have sold or donated than average, having done so in 93% of cases.
Roedd pobl â Chymhwyster Cenedlaethol ar Lefel 4 neu uwch hefyd yn fwy tebygol o fod wedi gwerthu neu roi na'r cyfartaledd, ar ôl gwneud hynny mewn 93% o achosion.