McCleary PVO Data Set - McCleary (2008)
McCleary PVO Data Set Excel file McCleary (2008)

Religion Adherence Data - McCleary and Barro (2005)

Adherents

American Religion Data Archive

Barrett's Christian Encycolpedia of Religion

Fox and Sandler Data Set on State Religion

The Hartford Institute for Religion Research

The Hudson Institute's Center for Religious Freedom

The International Social Survey Programme

Religious Movements on the Web and in the World

U.S. State Department's International Reports on Religious Freedom

World Values Survey