In Figure 1 and Figure 2 at the top of this release, data for 2012-13 until 2017-18 is based on 2010 SOs, while data for 2018-19 onwards is based on 2013 SOs.
Yn Ffigur 1 a Ffigur 2 ar frig y datganiad hwn, mae data ar gyfer 2012-13 tan 2017-18 yn seiliedig ar SO 2010, tra bod data ar gyfer 2018-19 ymlaen yn seiliedig ar SO 2013.