Religion Data Year

Reference year for religious composition data, indicating data currency for religious demographics.

Quick Reference

Unit

year

How It's Calculated

Year of census, survey, or official estimate used for religion percentage breakdowns. Extracted from source metadata in CIA World Factbook 2020 edition. Represents the survey or census year when religious affiliation was measured. Stored as integer year (e.g., 2020, 2015, 2010). May differ from ethnic_groups_year if collected in different surveys.

Why It Matters

The year of religion data indicates reliability and reflects changing religious landscapes. Recent data captures current trends (secularization in Europe, religious revival in some regions, conversions, missionary activity), while outdated data misses major shifts. Religious demographics are politically sensitive and affect policy debates (secular vs religious education, blasphemy laws, religious freedom, public holidays, dietary laws in institutions).

Understanding the Values

Current: 2020-2024 (very recent - high confidence in accuracy) Recent: 2015-2019 (reasonably current - minor changes expected) Moderate: 2010-2014 (outdated - secularization/revival trends may have shifted) Old: 2000-2009 (significantly outdated - generational change not reflected) Very Old: < 2000 (unreliable - does not reflect modern religious landscape) Trends affecting currency: - Secularization: Western Europe, North America seeing rapid decline in religious affiliation (5-10% per decade) - Religious revival: Some African and Asian countries seeing increased religiosity - Conversion: Christian growth in South Korea, China; Muslim growth in sub-Saharan Africa - Migration: Gulf states, Western Europe seeing major religious composition shifts due to immigration Examples: - China: Difficult to measure (state atheism, underground churches, unofficial Buddhism/Taoism) - Saudi Arabia: Nearly 100% Muslim by law (non-Muslim worship illegal) - India: Major shifts with Hindu nationalism, Muslim population growth, Christian conversions - US: Rapid rise of 'nones' (non-religious) - from 16% (2007) to 29% (2023) Note: This is metadata for the religion metric - helps users assess whether religious percentages reflect current reality or outdated surveys.

Related Metrics

Ethnic Groups Data Year

Reference year for ethnic group composition data, indicating data currency for ethnic demographics.

Total Population

Total number of people living in a country, based on census data and demographic estimates.

Religious Composition

Breakdown of population by religious affiliation, with percentages for major faiths.

Women in Parliament

Percentage of seats held by women in national parliaments (single or lower chamber).

Data Quality & Coverage

Coverage: 233 countries (CIA Factbook 2020) Update frequency: Static (CIA Factbook 2020 snapshot) Source: CIA World Factbook via local HTML parsing Limitations: Year represents source year cited in Factbook, often lags actual census by 2-5 years. Many countries do not collect religious data in censuses (US Census does not ask religion; France prohibits it). Self-reported affiliation vs practice differs vastly (cultural Christians/Muslims vs practicing). Governments may manipulate data for political reasons (undercount minorities, exaggerate majority). Pew Research provides more frequent estimates via surveys but not included in this dataset. Atheism/agnosticism often undercounted in religious societies due to stigma.