Over the summer of 2020 attendances increased and approached pre-COVID-19 levels in August, before falling in September and falling further through to December.
Dros fisoedd haf 2020 roedd nifer yr ymweliadau wedi cynyddu ac erbyn mis Awst roeddent bron wedi cyrraedd lefelau cyn COVID-19, cyn disgyn ym mis Medi a disgyn ymhellach hyd at fis Rhagfyr.