Worldwide Quaker population map, 2017

The Worldwide Quaker population map published by the Friends World Committee for Consultation's World Office is a primary institutional source, compiled by the body that exists specifically to coordinate communication among Quaker yearly meetings across the globe. Its figures draw on membership reporting from constituent yearly meetings themselves, giving it the best available aggregate picture of a famously decentralized and non-hierarchical religious body with no single central membership roll. The same decentralization that makes the Committee's coordinating role valuable also means individual yearly meetings vary in how rigorously and how often they update their own counts, so the resulting global total is a careful compilation of self-reported regional figures rather than an independently audited census.