In the 2011 census, 5.4 million Australians ticked the “Catholic” box, with a total Christian population of 13.1 million (61.1 per cent). Roughly 4.8 million people (22.3 per cent) said they had “no religion”.

The “no religion” option was introduced to the census in 1991. The ABS agreed to change the order after receiving more than 400 submissions alleging a bias in how the question was framed, because “no religion” appeared after nine religions and the “other” box, making it difficult to spot on a first glance.

Credit: Ruben Schade on Flickr, CC License.

The Australian reports that Bernard Salt, a demographer with KPMG, expected the change would prompt many to select the “no religion” box for the first time, but warned that the change could “muddy the waters” by making it more difficult to assess historical trends.

“I would expect that (figure of 22.3 per cent) to increase an order of magnitude at the next census — it might be 30 per cent or 33 per cent,” Mr Salt said. “It is not that there is a sudden increase in godlessness, it is simply there is a mechanism to capture what is ­already there in the community.”

The Sydney Morning Herald reports that Lyle Shelton, managing director of the Australian Christian Lobby, said, “Just because someone might tick no religion does not necessarily mean they are an atheist,” and added that the person could be agnostic.

“I think it is pretty clear that most [Australians] believe in the transcendent or in some form of God and in exploring that side of their humanity,” said Mr Shelton.

Governments use the ABS census data to allocate services and resources, as well as decide on spending programs including the school chaplaincy program. Should Christianity lose its position as the majority religion, the way the government chooses to spend money may be affected.