People with no religious affiliation make up the third-largest global group in a new study of the size of the world’s faiths, placing after Christians and Muslims and just before Hindus.
The study, based on extensive data for the year 2010, also showed Islam and Hinduism are the faiths mostly likely to expand in the future while, Judaism has the weakest growth prospects.
It showed Christianity is the most evenly spread religion, present in all regions of the world, while Hinduism is the least global with 94% of its population in one nation, India.
Overall, 84% of the world’s inhabitants, which it estimated at 6.9 billion, identify with a religion, according to the study entitled The Global Religious Landscape issued by the Pew Forum on Religion and Public Life today.
The “unaffiliated” category covers all those who profess no religion, from atheists and agnostics to people with spiritual beliefs but no link to any established faith.
“Many of the religiously unaffiliated do hold religious or spiritual beliefs,” the study stressed. “Belief in God or a higher power is shared by 7% of unaffiliated Chinese adults, 30% of unaffiliated French adults and 68% of unaffiliated US adults.”
Exact numbers for religious populations are impossible to obtain and estimates for the size of the larger faiths can vary by hundreds of millions. This study by the Washington-based Pew Forum appears to be one of the most extensive to date.
Pew Forum demographer, Conrad Hackett, said the 2 500 censuses, surveys and population registers used to compile the report did not allow a further breakdown to estimate the world population of atheists and agnostics.
“It’s not the kind of data that’s available for every country,” Hackett said. “A census will typically ask what your religion is and you can identify a number of particular affiliations or no religion.”
An age breakdown showed Muslims had the lowest median age at 23 years, compared to 28 for believers all around the world. The median age highlights the population bulge at the point where half the population is above and half below that number.
“Muslims are going to grow as a share of the world’s population and an important part of that is this young age structure,” Hackett said.
By contrast, Judaism, which has 14 million adherents or 0.2%of the world population, has the highest median age at 36, meaning its growth prospects are weakest.
Hackett noted that Israel, which has 40.5% of the world Jewish population, had a younger age structure than the US, where 41.1% of the world’s Jews live.
Global Christianity’s median age is 30 and Hinduism is 26. With a median age of 34, the growth prospects for religiously unaffiliated people are weak, the study showed.