The Pew Research Centre’s 'Forum on Religion & Public Life', conducted in 250 countries during 2010, found that there were 2.2 billion Christians in the world, some 32 per cent of its population.
Based on analysis of more than 2,500 censuses, surveys and population registers in 230 countries, the study found that the next such largest grouping were Muslims at 1.6 billion (23 per cent).
They are followed by the 1.1 billion worldwide, or 16 per cent, who have no religious affiliation and are about equal in size to the world’s Catholic population.
Next to these are the one billion Hindus (15 per cent), almost 500 million Buddhists (7 per cent) and 14 million Jews (0.2 per cent).
A further 400 million people (6 per cent) practice various folk or traditional religions, including African traditional religions, Chinese folk religions, Native American religions and Australian aboriginal religion
An estimated 58 million people, slightly less than one per cent of the world’s population, belong to other religions, including the Baha’i faith, Jainism, Sikhism, Shintoism, Taoism, Tenrikyo, Wicca and Zoroastrianism.
More than eight-in-10 people worldwide identify with a religious group, according to the study.
It estimates that there are 5.8 billion religiously affiliated adults and children around the world, representing 84 per cent of the 2010 world population of 6.9 billion.