1.Thearda.com
The ARDA provides free access to the most authoritative religion statistics, data and church membership reports from around the world, including Christian statistics and adherents data. The ARDA offers recent U.S. and international survey findings, local, national and global profiles of religion, and detailed demographic reports and maps of religious and protestant denominations in America. Relying on an archive of over 500 data collections, the Association of Religion Data Archives provides online tools and resources for educators, religious congregations, researchers, journalists, and anyone interested in religion statistics and data.