Comparisons between 2020 and 2021 for GDHI per head estimates are classed as unreliable due to a discontinuity in population data for some areas, caused by differences in the timing of census updates.
Yr eithriad i hyn yw'r sectorau gwestai a thai llety/gwely a brecwast lle na ellir cymharu â data 2019 oherwydd newid methodolegol yn 2020 a 2021.