In the last 100 years, the share of believers in the world has not declined linearly, but has experienced a sharp decline in the mid-20th century and a subsequent rebound. If in 1910 practically all the world's population was religious, by 1970 the share of non-religious people reached its peak, after which it began to decline due to demographic processes.

Key figures: how the balance has changed

Here are the data showing the dynamics over a century.

Why the share of non-religious increased and then fell

The rise of non-religiosity in the 20th century was linked to several factors. Communist regimes actively promoted atheism, and in Western countries, secularization was driven by disillusionment with institutional religion after world wars. By 1970, nearly 20% of humanity did not identify with any religion.

However, after 1970, the share of non-religious began to decline. The reason is demographics. In non-religious societies, such as Europe, North America, and East Asia, fertility is lower and the population is aging. At the same time, in religious regions, such as Africa, South Asia, and Latin America, fertility is significantly higher. As a result, the share of believers in the global population is growing not because people are becoming more religious, but because religious groups reproduce faster.

An important nuance: non-religious are not the same as atheists

It is important to distinguish these categories. Non-religious is a broad term that includes agnostics, people without a specific religious affiliation, and those who believe in something higher but do not belong to a specific denomination. Atheists are a subset, and their share has always been much smaller. For example, according to data from 2025, there are about 11% of non-religious people in the world, while only 1.79% are atheists.

What next

Projections for 2050 predict further decline in the share of non-religious — to about 8.7% of the world's population. The number of atheists is also expected to decline. Thus, the world is becoming not more secular but more religious — but not due to conversions, but due to fertility.

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