More than 80 percent of people around the world – about 5.8 billion individuals – identify with a religious group, according to a new study by the Pew Research Center.

"Christians number 2.2 billion, or about one-in-three" of the 6.9 billion people in the world in 2010, the study found, adding that about "half of all Christians are Catholic."

Released Dec. 18, the study examined censuses, surveys and population registers to determine the size, geographical distribution and age of the world's major religions.

As of 2012, the world contained about 1.6 billion Muslims, 1 billion Hindus, almost 500 million Buddhists and 14 million Jews, the analysis said.

Furthermore, over 400 million people, or six percent of the global population, adhere to folk or religious traditions. Less than one percent – about 58 million people – belong to other religions, including Jainism, Sikhism, Taoism, Zoroastrianism, Wicca and the Baha'i faith.

In addition, the study revealed that approximately one-in-six people throughout the world have no religious affiliation. Numbering about 1.1 billion, this group is the third largest globally, behind Christians and Muslims.

"However, many of the religiously unaffiliated have some religious beliefs," the study said, including a belief in God or participation in religious observances.

In six countries – the Czech Republic, North Korea, Estonia, Japan, Hong Kong and China – the religiously unaffiliated make up the majority of the population. China is home to 62 percent of the world's religiously unaffiliated people.

Overall, the unaffiliated are about equal in number to the Catholic population of the world.

"Overwhelmingly, Hindus and Christians tend to live in countries where they are in the majority," the study noted, adding that Muslims and the religiously unaffiliated also live in countries in which they are the predominant group, but by a smaller margin.
Out of 232 countries and territories in the study, 157 have Christian majorities, the analysis explained.

"Christianity has spread far from its historical origins and is geographically widespread," it found, observing that 99 percent of Christians live outside the region where the religion started.

About 37 percent of Christians are members of Protestant, Anglican, independent or nondenominational churches, while 12 percent are Orthodox.

Other traditions that view themselves as Christian – such as Mormons, Christian Scientists and Jehovah's Witnesses – make up about one percent of the Christian population.

As a whole, Christians have a median age of 30, slightly higher than the overall global population median of 28.

In addition, the analysis revealed that Christianity has roughly equal numbers in Latin America and the Caribbean, Europe, and sub-Saharan Africa.

"Of the major religious groups covered in this study, Christians are the most evenly dispersed," it said.