PBS, as part of its Frontline program entitled “Rumsfeld’s War” has 9 maps of the world that highlight countries in which U. S. troops have been deployed since 1969. The maps are broken out by presidential administration. By the looks of these maps, the U. S. has most of the world covered, although there is no indication as to the number of troops stationed in each country - although if you hover over an area it will provide you a breakdown by region. To view that you’ll need to refer to the U. S. Department of Defense Military Personnel Statistics.