Australia’s population in 1956 was about 9.5 million. The exact figure can vary a little depending on whether a source uses a mid-year estimate or census-related estimate, but that’s the right order of magnitude.

Context

A helpful comparison is that Australia was at about 9.2 million in 1955 and about 10.3 million by 1960 , so 1956 sits between those two points.

Note

The most authoritative historical population series is the Australian Bureau of Statistics’ historical population data.