The achieved sample size each month is approximately 1,000 (although it was higher in May 2020 at just over 3,000 respondents), and the response rate is around 74% of those asked to take part.
Maint y sampl misol a gyrhaeddir yw tua 1,000 (ond roedd yn fwy ym mis Mai 2020 pan oedd ychydig dros 3,000 o ymatebwyr) ac mae’r gyfradd ymateb tua 74% o’r rhai y gofynnwyd iddynt gymryd rhan.