Data from 2011 have been included in Figure 10 only insofar as they show the proportion of each qualification group who were able to speak Welsh.
Mae data 2011 wedi'i gynnwys yn Ffigur 10 er mwyn dangos cyfran pob grŵp cymhwyster sy'n gallu siarad Cymraeg ac i'r perwyl hwn yn unig.