There have been 248 mass killings in the USA since 2006 (about one every two weeks). The USA has 15 of the top 32 mass killings, so with only 4.3% of the population, the USA has 47% of the top mass killings.
http://www.usatoday.com/story/news/nation/2013/09/16/mass-killings-data-map/2820423/
http://www.statista.com/statistics/248845/number-of-victims-of-mass-shootings-in-western-democratic-countries/
http://www.theonion.com/articles/no-way-to-prevent-this-says-only-nation-where-this,36131
