Perhaps you've seen the reports in the news: the current population of 1.57 billion Muslims makes up 23% of the world's population. The data are from a Pew Study.

Details are here, including interactive maps. There is also a link to a PDF of the full report of 62 pages, which I have not yet gone over.

I wonder how many of the 1.57 billion are practicing Muslims? I wonder how many have taken, or are ready to take, the path of violent jihad? Even 1% would be a lot of folks.