Examining data in wave 7 (2017-22) of the World Values Survey, Professor Ryan Burge of Eastern Illinois University writes that Indonesia, the Maldives, Bangladesh, Jordan, and Nigeria are the most religious of 64 nations examined, while Czechia (the Czech Republic), Japan, the Netherlands, New Zealand, and Australia are the least religious.
Indonesia, located in Southeast Asia (map), is the world’s fourth most populous nation and has more Muslims than any other country. The nation is 80% Muslim, 12% Christian, and 2% ethnic religionist.
The Maldives and Jordan are 98% and 95% Muslim; Bangladesh is 89% Muslim and 9% Hindu. Nigeria, the most populous country in Africa and 6th most populous in the world, is 47% Muslim, 46% Christian (11% Catholic), and 7% ethnic religionist.