Thelema has no single organisation: its chief initiatory orders keep their own membership rolls, some of it oathbound material, and no outside survey covering the tradition as a whole was found.
What would resolve this A survey of the major Thelemic orders' own reported membership, or an independent sociological study using a stated, defensible definition of practice, aggregated across the tradition's known organised currents.
OpenSociology of religionHenrik Bogdan and Martin P. Starr (eds.), Aleister Crowley and Western Esotericism