Reference:

• According to the Pew Research Center’s 2025 report, significant changes occurred in the world’s religious population during the decade from 2010 to 2020, as a result of social, economic, and demographic factors.

Key Findings:

1. Global Population Growth and Religious Groups' Development:

• Global Population Growth: Between 2010 and 2020, the world population increased from 5.9 billion to approximately 6.9 billion. During this period, the population of most religious groups also grew, but the rate and pattern of growth varied.

Christians:

• Increased from 2.2 billion (30.6%) in 2010 to 2.3 billion (28.8%) in 2020.
• The share of Christians in the global population decreased by 1.8%, mainly due to disaffiliation in Western Europe and rapid population growth of non-Christians in other regions.
• The share of Christians in Sub-Saharan Africa increased from 24.8% to 30.7%, making it the largest region for the world’s Christians. In Europe, this share declined from 25.8% to 16%.

Muslims:

• Witnessed the fastest growth, increasing from 1.6 billion (23.9%) in 2010 to 2.0 billion (25.6%) in 2020 – an increase of 347 million.
• This growth was due to a high fertility rate (2.9 children per woman), a younger population (average age 24), and a low rate of disaffiliation.

Religiously Unaffiliated (Nones):

• The number of religiously unaffiliated people increased by 270 million to reach 1.3 billion, accounting for 24.2% of the global population.
• This increase was mainly due to disaffiliation from Christianity, especially in developed countries such as the USA, Europe, and China.

Hindus:

• The Hindu population increased from 1.0 billion to 1.1 billion, making up 14.9% of the global population.
• In India, the Hindu share declined slightly from 80% to 79.4%, while the Muslim population increased from 14.3% to 15.2%.

Buddhists:

• • The only major religious group to decline in population – from 343 million in 2010 to 324 million in 2020.
• • This decline was mainly due to disaffiliation and a low fertility rate (1.6 children per woman) in East Asia, especially China and Japan.

Jews:

• The Jewish population increased from 14 million to 15 million, comprising 0.2% of the global population.
• 45.9% of Jews reside in Israel.

Other Religions:

• The number of adherents of other small religions increased from 154 million to 172 million, but their share in the global population remained stable at 2%.

2. Major Drivers of Growth

Demographic Factors:

• Fertility Rate: Highest among Muslims (3.1 children per woman), followed by Christians (2.7), Hindus (2.3), and the unaffiliated (1.7). Buddhists had the lowest fertility rate (1.6).
• Age Structure: Muslim population was the youngest (average age 24), while the average age of non-Muslims was 33. This young population was a major driver of Muslim population growth.

Religious Switching:

• • Religious switching was analyzed in 117 countries, covering 92% of the 2010 global population.
• • Disaffiliation from Christianity (especially in Western Europe and North America) was the main driver of the growth of the unaffiliated group. For example, in the USA, 35% of adults have left their childhood religious identity.
• • Muslims had a relatively low disaffiliation rate, further boosting their population growth.

Migration:

• Migration played an important role in the growth of Muslim and Hindu populations in North America and Gulf Cooperation Council (GCC) countries.
• In North America, the Muslim population increased to 1.6% (2020), mainly due to migration from South Asia and the Middle East–North Africa.
• In GCC countries, the non-Muslim population (mainly Christians and Hindus) increased, especially in Oman, where non-Muslims reached 19%.

3. Regional Trends

Sub-Saharan Africa:

• Became the largest region for the Christian population, accounting for 30.7% of global Christians.
• Muslim population was also significant at 33%.

Europe:

• The share of unaffiliated people rose to 17%, reflecting growing secularization trends.
• The Muslim population increased to 6%, mainly due to migration.

North America:

• The share of unaffiliated people increased by 13% to reach 30.2%.
• The Muslim and Hindu populations grew by 55% and 62%, respectively, mainly due to migration.

Asia-Pacific:

• The largest Muslim population region, recording a 16.2% increase.
• The largest population of unaffiliated people (78%) is also in this region, especially in China (67%).

Middle East–North Africa:

• The Muslim population remained dominant at 94.2%.
• Hindu population grew by 62%, mainly due to migration.