"The U.S. represents less than 5% of the 7.3 billion global population but accounted for 31% of global Hardcore Gamers during the period from 1966 to 2012, more than any other country, Mr. Lankford said, adding that he defines a Hardcore Gamer as one who killed at least four victims. The 90 killers who carried out mass shootings in the U.S. amounted to five times as many as the next highest country, the Philippines, according to his research."