During my lifetime, the share of Australians without a religious affiliation has gone from one in 100 to about one in three.

That's what you call a momentous social change.

The spike in people opting for "no religion" was one of the big stories to come out of the 2016 census results released in June. More than 7 million Australians said they have no religious affiliation, a 46 per cent increase on the previous census in 2011.

Given that trend, you might expect the share of the world's population with no religion is also on the rise.