http://www.humanreligions.info/tags/no_religion.html
Main page:
Secularisation Theory: Will Modern Society Reject Religion? What is Secularism?Human Truth Foundation pages (4):
Religion in the United Kingdom: Diversity, Trends and Decline, in the following sections:
Religion in Europe: 1. Country by Country Comparison
Which are the Best Countries in Asia?: 11. Religion and Beliefs