16 to 34s and 35 to 54s were more likely to be in favour of the change (71% and 62% respectively) than those aged 55+.
Roedd pobl 16-34 oed a 35-54 oed yn fwy tebygol o fod o blaid y newid (71% a 62% yn y drefn honno) na'r rhai 55+ oed.