The largest reduction in population estimates was for Gwynedd, whose population was reduced by 6.2%, from 124,800 to 117,100.
Ar gyfer Gwynedd y gwelwyd y gostyngiad mwyaf mewn amcangyfrifon poblogaeth – roedd gostyngiad o 6.2% yn y boblogaeth, o 124,800 i 117,100.