The first section of the survey took part by telephone; respondents who used the internet were then asked to complete a short set of questions online.
Cynhaliwyd rhan gyntaf yr arolwg hwn dros y ffôn; gofynnwyd wedyn i ymatebwyr a oedd yn defnyddio'r rhyngrwyd gwblhau set fer o gwestiynau ar-lein.