In brief
The largest documented number lives in China: 677,521 people in the 2020 census.
Official figures exist for 2 countries; together they add up to 681,524. This is not an estimate of the world total: the censuses were held in different years (2019-2020) and define belonging differently, and countries without such data are not counted.
Where they live: census figures
Each figure comes from the country's official census. Censuses define belonging differently (self-identification, citizenship, mother tongue, ancestry); the type is given on each row.
China
677,521
Vietnam
4,003
Sum across 2 countries681,524
Sources
- United Nations Statistics Division (UNSD). Demographic Yearbook, table 26: Population by national and/or ethnic group. China, Census - de jure - complete tabulation, Final figure, complete. https://data.un.org/Data.aspx?d=POP&f=tableCode%3a26%3bsexCode%3a0%3bareaCode%3a0%3bcountr…
- United Nations Statistics Division (UNSD). Demographic Yearbook, table 26: Population by national and/or ethnic group. Viet Nam, Census - de jure - complete tabulation, Final figure, complete. https://data.un.org/Data.aspx?d=POP&f=tableCode%3a26%3bsexCode%3a0%3bareaCode%3a0%3bcountr…