A new, comprehensive demographic study of more than 230 countries and territories conducted by the Pew Research Center’s Forum on Religion & Public Life finds that more than eight-in-ten people worldwide identify with a religious group.
At the same time, the number of those unaffiliated with religion is on the rise, and now constitutes the third-largest global belief group.
The report estimates that there are 5.8 billion religiously affiliated adults and children around the globe, representing 84 per cent of the 2010 world population of 6.9 billion.
Based on analysis of more than 2,500 censuses, surveys and population registers, the study finds 2.2 billion Christians (32 per cent of the world’s population), 1.6 billion Muslims (23 per cent), 1 billion Hindus (15 per cent), nearly 500 million Buddhists (seven per cent) and 14 million Jews (0.2 per cent) around the world as of 2010.
In addition, more than 400 million people (six per cent) practice various folk or traditional religions, including African traditional religions, Chinese folk religions, Native American religions and Australian aboriginal religions.
An estimated 58 million people – slightly less than one per cent of the global population – belong to other religions, including the Baha’i faith, Jainism, Sikhism, Shintoism, Taoism, Tenrikyo, Wicca and Zoroastrianism, to mention just a few.
At the same time, the new study also finds that roughly one-in-six people around the globe (1.1 billion, or 16 per cent) have no religious affiliation.
This makes the unaffiliated the third-largest belief group worldwide, behind Christians and Muslims, and about equal in size to the world’s Catholic population.
Surveys indicate that many of the unaffiliated hold some religious or spiritual beliefs (such as belief in God or a universal spirit) even though they do not identify with a particular faith.
These are among the key findings of “The Global Religious Landscape: A Report on the Size and Distribution of the World’s Major Religious Groups as of 2010.”
The report is part of the Pew-Templeton Global Religious Futures project, which analyses religious change and its impact on societies around the world.
The project is jointly funded by The Pew Charitable Trusts and the John Templeton Foundation.
* Read the full report here: http://www.pewforum.org/global-religious-landscape.aspx 
* The demography of belief worldwide http://www.ekklesia.co.uk/node/17646