Census paints a picture of average Aussie

Family at a park.
The average Australian is a woman in her 30s living with a partner and children in a capital city. -AAP Image

The average Australian is a woman in her 30s living with a partner and children in a capital city, where her household earns at least $3000 a week.

That's the overview of the latest census data released by the ABS on Tuesday, but the full picture of Aussie life is far more complex.

The nation's population has reached 25.4 million as of 2021, growing by about two million since the previous census in 2016.

The number of residents born overseas, or with a parent born overseas, has increased to more than 50 per cent.

Four in five Australians live on the east coast.

More than one million new migrants arrived in Australia in the four years to 2021, about 80 per cent of them coming before COVID-19.

The top five ancestries reflected previous trends with English first and Australian second, followed by Irish, Scottish and Chinese.

England also topped the list for birthplaces outside of Australia, followed by India which leapfrogged China and New Zealand. The Philippines rounded out the top five.

The largest population increase was in the ACT which has grown by 50 per cent since 2001, and almost 15 per cent since 2016, to just shy of 455,000.

Australia's millennial generation is also becoming the nation's largest, catching baby boomers. Both demographics comprise 5.4 million people, but the 2021 statistics reflect a diminishing number of boomers compared to 2016.

Defined as the generation of people born between 1946 and 1964, the number of baby boomers fell from 25.4 per cent to 21.5 per cent of overall population. Millennials, born between 1981 and 1996, increased from 20.4 to 21.5 per cent.

In 1966, baby boomers made up up nearly 40 per cent of all Australians.

As the population increased, so did its proportion of Indigenous Australians, reaching 3.2 per cent in 2021 from 2.8 per cent in 2016.

The rise in the number of Indigenous Australians to more than 810,000 represents a 25 per cent spike since 2016.

ABS statistician David Gruen said it represents more than a jump in the actual population, also showing "an increasing number of people who self-identify" as Indigenous.

The 2021 census data shows an increase of about 50 per cent in the number of Indigenous people over the age of 65, Dr Gruen said.

The census was conducted in August 2021 during the height of COVID-19 restrictions and lockdowns, with two million extra people at home on census night compared to 2016.

COVID-19 also led to an 80 per cent decrease in the number of overseas visitors, with 61,860 in 2021 compared to more than 315,000 in 2016.

Almost 80 per cent of respondents completed the census online.

Since 2016 almost one million new private dwellings were added, with more than 11 million counted across the nation.

Separate homes accounted for 70 per cent of them, while 16 per cent were apartments and 13 per cent were townhouses. The proportion of apartments continues to increase.

Christianity remains the nation's most prevalent religion, with 43.9 per cent of people identifying with the denomination. However, the figure has fallen from more than 60 per cent a decade earlier.

Almost 40 per cent of respondents classified themselves as 'not religious' compared with 22.3 per cent in 2011.

The most recent census included new questions about Australian Defence Force participation, with almost 600,000 current or former members.

"The data collected in this census will enable delivery of more targeted services for Australian veterans," Dr Gruen said.

"Our largest age group of those who have previously served are in their 70s and this will include many who served in Vietnam."

Some eight million people reported a long-term health condition.

The 2021 census contained 65 questions and produced 10 million data tables.

It was the first time people could select non-binary as a gender option.