More than 900 people died in mass shootings during the past seven years, and a majority of them were killed by people they knew, according to USA TODAY.

The 934 deaths account for less than 1% of all gun-related homicides, and nearly half involve a suspect slaying his or her family members, the detailed examination shows. USA TODAY said it combed through FBI records and news accounts to identify 146 mass shootings since 2006 that matched the FBI definition of mass shooting, where four or more people were killed.

A separate analysis of 56 mass shootings since 2009 provided to USA TODAY by a group of mayors promoting gun control reaches similar conclusions. More than half – 57% – of cases examined by Mayors Against Illegal Guns involved domestic violence. The group, co-founded by New York City Mayor Michael Bloomberg, is made up of more than 850 U.S. mayors.

In all, 934 people have died in mass shootings over the past seven years, the USA TODAY analysis shows. In the 71 shootings that involved someone killing his or her family members, 376 victims died. Most of those killings occurred at home. Dozens more were killed by acquaintances, neighbors and co-workers.

The USA TODAY analysis included all the events in the mayors' study, but also dozens of others. FBI homicide records, supplied by local police, are incomplete and do not include cases from states such as Florida, which the newspaper added to its study.