Lauren Keim was raised a Catholic and regularly went to church as a teenager. But she never believed in God and realised at 12 she had always been an atheist. It was easier for her as a child to believe in Santa Claus and the Easter Bunny.

''I had good evidence for those things and no evidence for good of any sort of higher power,'' she said. ''Santa came every year and delivered me presents; it was pretty hard to argue with that concrete evidence.''

Ms Keim, 34, of East Brunswick, who has a number of university degrees, is not unusual for her generation. As a Social Trends report by the Australian Bureau of Statistics highlights, the young and those with degrees are more likely to eschew any religious identification.

Just under 4.8 million Australians, or 22 per cent of the population, stated they had no religion on census forms two years ago. The fastest growth was in those aged 15 to 34.

The trend is accelerating. In 1911, Australia was unusual in giving its citizens an option of saying they had no religion on census forms. Then just 10,000 people did so, or 0.4 per cent of the population.