The total number of Christians worldwide is 2.18 billion, or 31.7 percent of the estimated global population of 6.9 billion, a new study has said.
"Christians are also geographically widespread -- so far-flung, in fact, that no single continent or region can indisputably claim to be the center of global Christianity," the Pew Research Center said.
Christians make up as big a proportion of the world's population as they did a century ago, but whereas two-thirds of them in 1910 were in Europe, they now are spread more widely throughout the world.
"Christianity today -- unlike a century ago -- is truly a global faith," said the Pew Research Center in the executive summary of its report, "Global Christianity," produced by its Pew Forum on Religion and Public Life unit.
Half of all Christians are Catholics, while 36.7 percent are Protestant and 11.9 percent Orthodox, according to the study.
The United States, Brazil and Mexico led the list of nations with the largest number of Christians, with Russia, the Philippines and Nigeria having the biggest numbers in Europe, Asia-Pacific and Africa respectively.
Pew Research Center said it based its findings, posted on its website (www.pewforum.org), primarily on a country-by-country analysis of about 2,400 data sources, including censuses and population surveys.