Between 1982 and 2011, a mass shooting occurred roughly once every 200 days. However, between 2011 and 2014 that rate has accelerated greatly with at least one mass shooting occurring every 64 days in the United States.[116] In "Behind the Bloodshed", a report by USA Today, said that there were mass killings every two weeks and that public mass killings account for 1 in 6 of all mass killings (26 killings annually would thus be equivalent to 26/6, 4 to 5, public killings per year).[117] Mother Jones listed seven mass shootings, defined as indiscriminate rampages in public places resulting in four or more victims killed,[118] in the U.S. for 2015. The average for the period 2011–2015 was about 5 a year.[119] An analysis by Michael Bloomberg's gun violence prevention group, Everytown for Gun Safety, identified 110 mass shootings, defined as shootings in which at least four people were murdered with a firearm, between January 2009 and July 2014; at least 57% were related to domestic or family violence.[120][121] This would imply that not more than 43% of 110 shootings in 5.5 years were non-domestic, though not necessarily public or indiscriminate; this equates to 8.6 per year, broadly in line with the other figures.