Even when we use coding choices that are most charitable to Lankford, such as excluding any cases of insurgencies or battles over territory, his estimate of the US share of shooters falls from 31 percent to 1.43 percent. It also accounts for 2.1 percent murders, and 2.88 percent of their attacks. All these are much less than the United States’ 4.6 percent share of the population.
https://nypost.com/2018/08/30/america-doesnt-actually-lead-the-world-in-mass-shootings/