In my original reply there's a brief bit of me discussing the US averaging 2 or 3 a year and how that compared up with other countries with smaller population like Norway, and then general stream of crime per capita, but that was the only list I could find... I did encounter your Rampage Killings list when try to relocate the one I'd quoted but it does not paste properly into Excel and individually counting them all and comparing wasn't something I was in the mood for. You'll also note the list of citations is thin and doesn't include - that I saw - any citation of some formal table or research. It may or may not be accurate, but I'm choosing to assume that the list is light on all fronts, and thus is missing non-US incidents as well, and proportionally. The list you attached is 'Americas' so it's hard to compare to Europe, but I will note that the 'Americas' list was 116 entries and Europe's was 99, and that the Americas have 900 million people in them. True, most of the rampages listed are in the US but I'd distrust data from almost anywhere south of the Rio Grande much as I would East of Berlin. My personal guess is the US does have more of these, but I think it's within some single to double digit percentage rather than some order of magnitude thing like 10x.