 Mixed race people are the fastest growing ethnic group in the UK and numbered 1.25 million in the 2011 census.A number of academics have pointed out that the ethnicity classification employed in the census and other official statistics in the UK since 1991 involve confusion between the concepts of ethnicity and race.Aspinall notes that sustained academic attention has been focused on "how the censuses measure ethnicity, especially the use of dimensions that many claim have little to do with ethnicity, such as skin colour, race, and nationality".