Christianity is a very easy religion to follow. we are not required to forsake certain earthly pleasures such as drinking or pork. The mongols of Genghis Khans time were intrigued with Christianity for these very reasons.

Cute Wolf is right however, the vast majority of people in the world right now are religion in name but not practice. However, compared to America the middle east is far more religious because of the very culture. The vast majority of Middle easterners are Muslim, therefore it is easier to be a practicing Muslim in the middle East than it is in America or some other highly diversified society.