What does the Census question on religion really say about us?

The Australian Census is upon us. Among the questions that statisticians will be keenly poring over is a fairly simple one: what is the person's religion?There have been huge shifts in Australia's religious make-up since the Census began more than 100 years ago.In 2021, Christianity was still the most common response, but it had dropped by a million since 2016. In the meantime, the number of people ticking the box for "no religion" has risen, accounting for 39 per cent of responses in the last Census.Answering this question isn't always straightforward though. So what does it say about us?