A global study of religious adherence has found that about one out of every six people worldwide has no religious affiliation. To put it into perspective, that is about equal to the amount of Catholics in the world!

The results were released yesterday by the Pew Research Center, and is entitled, “The Global Religious Landscape.” It is based on analysis of 2 500 different data sources – including censuses and demographic surveys of children and adults in 232 countries. It relies on self-identification, so it includes people who are not regular practitioners or orthodox believers of the religion they claim. The full report can be read here.

Conrad Hackett, the primary researcher on the report, says a lot of people will be surprised by their findings:

Something that may surprise a lot of people is that the third-largest religious group, after Christians and Muslims, is the religiously unaffiliated. There may have been some guesses floating out there before, but this is the first time there are numbers based on survey data analyzed in a rigorous and scientific way.

More than three-quarters of the “religiously unaffiliated” live in Asia, with the majority in China. Many of the people in this group do hold some religious or spiritual beliefs and “may even believe in a deity, but they do not identify with a particular faith”.

Over all, Christians are the largest religious group, with 2,2 billion people – about 32% of the world’s population. They are followed by Muslims, with 1,6 billion (about 23%). There are about one billion Hindus, about 15% of the global population, and nearly half a billion Buddhists – about 7%.

One of the other interesting findings by the study sees a wide disparity in the median age of religious populations. For instance, Muslims and Hindus are the youngest, while Buddhists and Jews are the oldest. The median age of the youngest group, Muslims, was 23, while the median for Jews was 36.

[Source: NY Times]