Since then the trend has been broadly downward and in October 2021, monthly performance was the lowest since comparable data was first recorded in April 2012.
Ers hynny, bu tuedd tuag i lawr yn gyffredinol, ac ym mis Hydref 2021 roedd y perfformiad misol ar ei lefel isaf ers i ddata cymaradwy ddechrau cael ei gofnodi ym mis Ebrill 2012.