The country has an area of 2.9 million square miles and a population of 21 million. According to the 2006 census, 64 percent of citizens consider themselves to be Christian, including 26 percent Roman Catholic, 19 percent Anglican, and 19 percent other Christian. Buddhists constitute 2.1 percent of the population, Muslims 1.7 percent, Hindus 0.7 percent, Jews 0.4 percent, and all others professing a religion 0.5 percent.
At the time of European settlement, aboriginal inhabitants followed religions that were animistic, involving belief in spirits behind the forces of nature and the influence of ancestral spirit beings. According to the 2006 census, 5,206 persons, or less than 0.03 percent of respondents, reported practicing aboriginal traditional religions, down from 5,244 in 2001. The 2006 census reported that almost 64 percent of Aborigines identify themselves as Christian and 20 percent listed no religion.
In 1911, during the first census, 96 percent of citizens identified themselves as Christian. In recent decades traditional Christian denominations have seen their total number and proportion of affiliates stagnate or decrease significantly, although from 2001 to 2006, the total number of Pentecostal and charismatic Christians increased by 12.9 percent. Over the past decade, increased immigration from Southeast Asia and the Middle East considerably expanded the numbers of citizens who identify themselves as Buddhists, Hindus, and Muslims and increased the ethnic diversity of existing Christian denominations. Between 2001 and 2006, the numbers increased for Buddhists by 17 percent (to 418,000), Muslims by 21 percent (to 340,393), Jews by 6 percent (to 89,000), and Hindus by 55 percent (to 148,131). In 2006 approximately 18.7 percent of citizens considered themselves to have no religion, up from 17 percent in 2001, and 11.2 percent made no statement regarding religious affiliation. According to a 2002 survey, 23 percent of adults had participated in church or religious activities during the previous three months.