Islam has been at war with non Islamic countries for thousands of year...and they still are. According to Wiki and there are other sites
"Conversion to Islam in U.S. prisons refers to the contemporary high rate of conversion to Islam in American prisons, for which there are a number of factors. It is the fastest growing religion in U.S. prisons, where the population is 18 percent Muslim; 80 percent of all prison religious conversions are to Islam. "
Naturally, there are reasons why this is happening and it is not just due to accident. One thing I've been told is that Islam worship allows cross pollination of whatever a group of cells is called with another group of cells for longer and maybe multiple times a day. It is my understanding that doesn't take place with other religions inside jails, but I could be wrong on "some" of what I said. I just know there are suppose to be some incentive to go to Islam worship.
Then we have the religion of peace being active everywhere..
Is Islam really a Religion of Peace? What makes Islam so different?
www.thereligionofpeace.com