Overall, 84 per cent 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 on Tuesday.

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.