This is a decrease of 0.1% between 1 December 2021 and 1 December 2022, and a decrease of 0.8% from the peak on 2 March 2020.
Mae hyn yn ostyngiad o 0.1% rhwng 1 Rhagfyr 2021 ac 1 Rhagfyr 2022, ac yn ostyngiad o 0.8% ers y brig ar 2 Mawrth 2020.