The first round of 2021 census key data from the Australian Bureau of Statistics (ABS) is finally here — remember filling it out in August in lockdown? — and it has revealed Australia is growing, changing and is more diverse than ever before.

The official population in August 2021 was 25.4 million people, up from 23.4 million from the last census in 2016. The data also revealed some pretty significant cultural changes. So what do we know? Let’s dive into the juicy stuff.

Census 2021 shows Australia has a migrant majority

Australia is now officially a nation with a migrant majority. About 51.5 per cent of residents were either born overseas or have a parent born overseas. The top three countries of birth among residents are Australia, England and India, which skipped over China and New Zealand since the last census.

About 5.5 million Australians speak a language other than English at home, up by 800,000 since 2016. Of that total 850,000 reported not speaking English well or at all.

Mandarin is still the most common language other than English spoken at home. Arabic is the second most common and Punjabi third, which increased by more than 80 per cent since 2016.

When asked about “ancestry” however, the top responses were English (33 per cent), Australian (29.9 per cent), Irish (9.5 per cent), Scottish (8.6 per cent) and Chinese (5.5 per cent).

Millennials are now the largest generation

Previously Baby Boomers held the biggest share but I guess they were pretty productive because we somehow skipped Gen X and now Millennials are the dominant gen.

Australians aged 25 to 39 were neck and neck with their parents as the largest chunk of the population, both on 21.5 per cent.

Millennials are born between 1981 and 1995 and have increased from 20.4 per cent of the population in 2011 to 21.5 per cent last year as older generations have passed. Boomers are born between 1946 and 1965 and have decreased from 25.4 per cent of the population in 2016. Looks like Boomers’ time in the sun and the centre of Australian policy is coming to an end. Sorry mum.

First Nations population is growing

More than 812,000 people identified as Aboriginal and Torres Strait Islander on census night, or about 3.2 per cent of the total population. This is an increase of more than 25 per cent since 2016.

But the population is also ageing. More than 47,000 people were 65 or older which is more than double the 2011 figure.

Religion is dwindling

For the first time fewer than half of Australians identified as Christian at just 43.9 per cent of the population. In the first ever census in 1911 it was 96 per cent. It remained in the 90s until 1966 when it started to decline and has been on a downward trajectory since.

The number of Australians who said they had “no religion” also rose dramatically from 30.1 per cent in 2016 to 38.9 per cent in 2021. In the 1960s less than 1 per cent of Aussies identified as having no religion.

Mental health is a big problem

For the first time the census collected data on long-term health conditions including mental health and found that the most common conditions were mental health conditions like anxiety and depression.

2,231,543 people reported a mental health condition in 2021. About 8 million reported long-term health conditions, of which asthma and arthritis were the most common.

We have same-sex marriage this time

This census was the first to collect data on same-sex marriages since they were legalised in 2017.

Almost 23,914 same-sex couples have married since then.

But marriage itself is trending downwards. In 2021 46.5 per cent of the population aged over 15 (side note: why they not counting from over 18 here…?) was registered as married. In 1991 that figure was 56.1 per cent.

We won’t know non-binary data until October

This was the first census to have a non-binary box in the gender section. Previously it just had male, female and “other”. But we won’t know the number of non-binary Aussies until later this year.

Only the so-called key population data was released on Tuesday. The second round of data will be released in October and the rest will come in 2023.

“Later this year, the ABS will be doing more analysis on non-binary sex responses and … working in consultation with key stakeholders in the LGBTQ+ community to understand the complexities, data quality and usefulness of the data,” an ABS spokesperson said in a statement.

It was good to see non-binary people be recognised but the ABS been criticised for erasing transgender and intersex people by failing to provide additional categories.