Australia's population counted in April 1921 was 5,435,700, "exclusive of full-blooded aborigines".
The Statistician independently estimated the number of aborigines, both "full-blood" and "half-caste" by obtaining figures from police and protectors of aborigines throughout the country.

One of the significant findings of the 1921 census was the low rate of males to females in the 20–30 age group, showing the impact of World War I on the population.

The 1921 census introduced automatic machine tabulation equipment, hired from England for the census.
Three punched cards were used to store individual, dwelling, and family information.
The cards were processed using an electric sorting machine prior to final totalling with an electric tabulator machine, devised by Herman Hollerith.

The census was subsequently conducted in 1933, 1947, 1954, and every five years from 1961 onwards.
Australia's population counted in April 1921 was 5,435,700, "exclusive of full-blooded aborigines". The Statistician independently estimated the number of aborigines, both "full-blood" and "half-caste" by obtaining figures from police and protectors of aborigines throughout the country.
One of the significant findings of the 1921 census was the low rate of males to females in the 20–30 age group, showing the impact of World War I on the population.
The 1921 census introduced automatic machine tabulation equipment, hired from England for the census. Three punched cards were used to store individual, dwelling, and family information. The cards were processed using an electric sorting machine prior to final totalling with an electric tabulator machine, devised by Herman Hollerith.
The census was subsequently conducted in 1933, 1947, 1954, and every five years from 1961 onwards.
Census in Australia