With the swearing in of arguably Australia's most religious modern Prime Minister - how many contenders for the top job can say they considered becoming priests? - the role and relevance of religion gives me pause for thought.

When Mr Abbott was awarded his Rhodes Scholarship in 1981 a large majority of Australians identified as Christians. Today, as he sets about as Prime Minister, that majority is slipping.

According to the Australian Bureau of Statistics, 22.3% of respondents declared they had "no religion" in the 2011 census. It's a number that has been rising, too. In every national census since 1933 - when just 0.3% of the population claimed irreligion - there have been increases in the numbers of self-declared atheists, agnostics and non-religious persons. The only exception was for the 2001 census, when there was a 0.9% drop along with a 2.9% decrease among all Christian denominations. But was also paired with a 2.7% increase in instances where a respondent chose to give no answer or gave an inadequately described affiliation.

So it would appear that secularism is on the rise. But why?

Religious institutions are among the oldest organisations in the world and their age comes with a cost. The inertia generated by their long-held traditions mean they are some of the slowest to respond to modern values and culture.

In the United States, institutionalised racial segregation ended in the 1960s with activists like Martin Luther King, Jr. and Rosa Parks. Though nearly a decade on, until 1978, the Church of Jesus Christ of Latter-Day Saints still refused to allow African-Americans to become priests. Their holy book supported this view, too. In the Book of Mormon, the disobedient Lamanites were 'cursed' with dark skin. However, when they repented of their sins, their skin became fair and their 'curse' removed.

Of course, there are plenty of holy interpreations and religious teachings here in Australia which offer misguidance. A 2008 report by the Islamic Women's Welfare Council of Victoria claimed that local imams aimed to preserve family units in spite of domestic abuses. A report in 2012 also suggested that while there was insufficient data for Muslim women, "women from culturally and linguistically diverse backgrounds are over represented as clients of the Women’s Domestic Violence Service of Victoria."

In cases of rape between legally separated couples, "advice women received from the imams was that it was "halal" - permitted - because there was a valid "nikah" - marriage," the 2008 report said.

These extreme cases of damaging religious beliefs are hopefully rare. But as we have just seen in the recent election, opposition to same sex marriage is largely a faith-based issue which the religious have no qualms about declaring in public.

But the Bible is bubbling with various dubious moral standards. From the commanding of slavery (Ephesians 6:5, Exodus 21:20-21, 1 Peter 2:18) to rape and kidnapping (Judges 21:10-24; Judges 19:25-28), child sacrifice (Exodus 13:2, Leviticus 27:28-29, Genesis 22:2, Psalm 137:9), the support of sexism (1 Timothy 2:12, Ephesians 5:22), and the systematic genocide of innocent people (1 Samuel 15:3, Exodus 34:11-14, Leviticus 26:7-9). It's all in there with the talking snake and the 'love your neighbour' bit.

Most local councils won't wish us a 'Merry Christmas' on street banners this year but rather offer a 'Season's Greetings' or similarly benign, secular statement.

It's a sign of the times, I think, but probably not one we can attribute to a higher power.

Tom Burns is a blogger, vlogger and self-confessed political junkie.