The U.S. is “one of the largest Muslim countries in the world.”
The percentage of Muslim population in North America is 1.71
http://www.muslimpopulation.com/America/
It’s hard to get absolute figures as most are several years old but in 2011 it was stated that;
There are 2.75 million Muslims living in the United States, a majority of whom, 63 percent, are first-generation immigrants. — Pew Research Center
As of March 2012, the population of the United States was 311,591,917 people.