Well, here’s an interesting dataset from John Lott in (of all places) The Chicago Tribune.
Over the course of 18 years, from 1998 to 2015, our list contains 2,354 attacks and at least 4,880 shooters outside the United States and 53 attacks and 57 shooters within this country. By our count, the U.S. makes up 1.49 percent of the murders worldwide, 2.20 percent of the attacks, and less than 1.15 percent of the mass public shooters. All these are much less than America’s 4.6 percent share of the world population.
While Americans are rightly concerned by the increased frequency and severity of mass public shootings, the rest of the world is experiencing much larger increases in per capita rates of attack. The frequency of foreign mass public shootings since 1998 has grown 291 percent faster than in the U.S.