Australians are increasingly less likely to worship a god and more likely to come from immigrant families.

The 2021 census revealed a growing nation – over 25 million people – that is more diverse than ever.

It also depicts a country undergoing significant cultural changes.

For the first time, less than half of Australians identified as Christian, although Christianity remained the most widespread religion in the country (reported by 43.9% of the population).

Meanwhile, the number of Australians who said they had no religion rose to 38.9% (from 30.1% in 2016).

The data also shows that almost half of Australians had an overseas-born parent and more than a quarter were overseas-born themselves.

The census – a national household questionnaire carried out every five years – took place in August last year amid the worsening COVID-19 pandemic.

The country’s two megacities, Sydney and Melbourne, were in lockdown, and people from the New South Wales, Victoria and ACT region were set to join them.

Yet Australian statistician David Gruen said the census was a success despite this challenge, with the household response rate rising to 96.1% from 95.1% five years earlier.

About four out of five households submitted their responses online.

The Australian Bureau of Statistics (ABS) will start releasing census results today and will release more data in the coming months.

The information helps governments improve their services and helps researchers and businesses better understand the community.

Family beliefs and traditions change

Christianity was the declared religion of around 90% of Australians until 1966, when its dominance began to decline.

The ABS says migration has affected trends since, although much of the change is due to the growth of atheist and secular beliefs.

The fastest growing religions, according to the latest census, are Hinduism (2.7% of the population) and Islam (3.2%), although these followers remain small minorities.

The 2021 census was also the first to collect data since same-sex marriages were legal in Australia.

Nearly 24,000 of these marriages have been officially registered.

However, marriage itself is less and less widespread.

A generation ago (in 1991), 56.1% of Australians over the age of 15 were married. This figure has now fallen to 46.5%.

New Australians increasingly come from India

Australia has long been one of the top immigration countries in the world, accepting more people than most other countries.

Last year, almost half of the population (48.2%) were first or second generation migrants, with at least one foreign-born parent. This compares to 41.1% 30 years ago.

Of the 27.6% of Australians themselves born overseas, the most common country of birth was England.

However, India has become the second most common source country, overtaking China and New Zealand.

The census also asked Australians to report their “ancestry”, as opposed to their country of birth or ethnicity.

The most common responses were English (33%), Australian (29.9%), Irish (9.5%) or Scottish (8.6%), with an additional 5.5% for Chinese.

Census expands to take into account illness and veterans

Last year’s census was the first to collect information on Australians’ long-term illnesses as well as people’s military service.

The most frequently reported chronic conditions were mental illness, arthritis and asthma.

The likelihood of Australians reporting long-term illnesses increased with age.

Women were also more likely to report a prolonged health condition.

Among children under 15, asthma was the most common condition, affecting 7.4% of boys and 5.3% of girls.

Meanwhile, more than half a million Australians (581,139) told ABS they had served or were serving in the Australian Defense Force (ADF).

The vast majority were men (86.6%). Most were former personnel (85.4%) rather than active duty.

The question on ADF service was included due to lack of information about veterans in the community.

Dr. Gruen said the responses would be used, along with other government documents, to help plan services for veterans.

The first version of the census data will be published on the ABS website from 10:00 a.m.