Demographics
Of the five autonomous regions, only Tibet has an absolute majority (>50%) of the designated ethnic group, namely, the Tibetans. Xinjiang has a plurality (<50%) of the designated ethnic group, the Uyghurs, though this is disputed by Uyghur independence advocates, who claim that the Han Chinese population in Xinjiang has been severely understated. The remaining 3 autonomous regions have absolute majorities of Han Chinese, the majority ethnicity of China.
Read more about this topic: Autonomous Administrative Divisions Of The People's Republic Of China