The Pew Forum on Religion & Public Life just released the results of a global study of Muslims. The interactive map lets you hover over a country and see what percent of its population is Muslim, and what percent of all Muslims reside there. It will be a surprise to many people to see what a small proportion of Muslims live in Arab countries.

Muslims

This map weights each country by population size (larger version here):

world-distribution-weighted

By region:

Pie-chart

Full report here.