Religious Demographics

While either Christians or Muslims make up the largest religious group in nine-in-ten nations around the globe, the religiously unaffiliated rank second in size in most of the Americas and Europe, as well as in many countries in sub-Saharan Africa.

Having a spouse of the same religion may be less important to many Americans today than it was decades ago.

Fact Tank sat down with David Campbell, a professor of political science at the University of Notre Dame, to explore what the new findings mean.

Two-thirds (66%) of U.S. Mormon adults are currently married, down slightly from 71% in 2007 – but still high compared with current rates among Christians overall (52%) and U.S. adults overall (48%).

In recent years, the share of Americans who identify with mainline Protestantism has been shrinking significantly, a trend driven partly by generational change.

One big reason evangelical Protestants have not declined at the same rate as other major Christian groups is that they are gaining new converts at a greater rate than they are losing people who were raised in the tradition.

The growth of the religiously unaffiliated in the U.S. is occurring across genders, generations and racial and ethnic groups.

The 35% of Millennials who do not identify with a religion is double the share of unaffiliated Baby Boomers (17%) and more than three times the share of members of the Silent generation (11%).

Christians are declining, both as a share of the U.S. population and in total number, while religious "nones" continue to rise.