A recent study by the University of Chicago, “Belief about God across Time and Countries,” combined research since 1991 along with recent research regarding belief in God across thirty different countries.
-Countries with the strongest belief in God were strongly Catholic societies, such as the Philippines.
-The United States also stood out for its high belief in God among developed countries with large Protestant populations.
-The study also reports that atheism is the strongest in northwestern Europe, especially in Scandinavia and in those countries that were once part of the Eastern Bloc–excluding very-Catholic Poland.
Overall, belief in God is declining worldwide, however, it is increasing in Russia, Slovenia, and Israel. The study did state that belief in God increases with age, older people more likely to belief and have always believed in God than younger people.
For more on the study and better writing (haha), check out the article released by the University of Chicago News.