The average had been rising slowly since 2018 but increased noticeably from April 2020 (the start of the pandemic), remaining at about 6.0% before decreasing from January 2021.
Roedd y cyfartaledd wedi bod yn cynyddu yn araf ers 2018 ond cynyddodd yn amlwg o Ebrill 2020 (dechrau’r pandemig).