The Christian population has shifted dramatically over the last century away from Europe to Africa, Asia and the Americas, yet Christians overall remain the largest religious group in the world, according to a new analysis released Monday.
Europe is home to about one-quarter of the world's Christians, compared with two-thirds a century ago, according to the Pew Research Center's Forum on Religion & Public Life. About one-quarter of the global Christian population can now be found in sub-Saharan Africa, while 37 percent live in the Americas, and 13 percent reside in the Asia-Pacific region.
Brazil has twice as many Catholics as Italy, while Nigeria has more than twice as many Protestants as Germany, where the Protestant Reformation began, the study's authors said.
Despite these changes, Christians are still the world's largest faith group, with nearly 2.2 billion adherents. Muslims comprise the second-largest group, with about 1.6 billion people, or slightly less than a quarter of the global population, the study's authors said.
Pew compiled the study from national censuses, population surveys, estimates from church groups and other sources in which respondents identified their religion. Analysts compared the findings with surveys from 1910, including data from the Center for the Study of Global Christianity at Gordon-Conwell Theological Seminary in South Hamilton, Mass.
The shifting Christian population has been a major concern of church leaders, as they try to build stronger ties with fellow believers across geographical boundaries and reconcile differing views of the Bible.
As just one example, mainline Protestants in the developing world tend to be more theologically conservative than church members in the United States and Western Europe. The tensions have been most visible in the global Anglican Communion since 2003, when the Episcopal Church, which is the Anglican body in the United States, elected the first openly gay bishop, V. Gene Robinson of New Hampshire. The 77 million-member fellowship has been fracturing ever since.
Pew researchers concluded that the Christian population is so widely distributed that no specific region can claim to be the center of the faith.
The smallest concentration of Christians can be found in the area where the faith began, the Mideast and North Africa, where Christians are only about 4 percent of the population. Egypt has the largest Christian population in the region, with about 4.3 million Christians, mostly Orthodox, who have been targets of violence, especially in the upheaval since the fall of President Hosni Mubarak.
Still, all but 10 percent of the world's Christians live in countries where they are the religious majority, according to the study.
The countries with the largest number of Christians are the United States, Brazil, Mexico and Russia. Christians comprise nearly 80 percent of the U.S. population, and about 74 percent of Russian citizens.
About 5 percent of China's residents, or 67 million people, are Christian, according to the study's authors. However, accurately estimating China's Christian population is notoriously difficult, due to the mix of government-sanctioned churches and grassroots house churches that operate illegally underground.