According to a new study, there are currently 2.18 billion Christians in more than 200 countries around the world.
They represent nearly a third of the estimated 6.9 billion 2010 global population.
The study, conducted by the Pew Research Center's Forum on Religion & Public Life, found Christians to be so geographically widespread that no single continent or region can claim to be the centre of global Christianity.
The Pew study, Global Christianity: A Report on the Size and Distribution of the World's Christian Population, says that 100 years ago, two-thirds of the world's Christians lived in Europe but today only about a quarter of all Christians live there.
More than one-third of Christians reside in the Americas; about a quarter live in sub-Saharan Africa and 13 per cent live in Asia and the Pacific.