Mass-casualty shootings are happening with greater frequency, and with higher death counts. Less than 16 months after the Pulse nightclub shooting in Orlando, Florida, set a terrible new benchmark for carnage, a gunman firing from his Las Vegas hotel room killed at least 58 people and wounded hundreds more.

The ‘Worst’ Mass Shootings in Modern U.S. History

Source: Mother Jones

*Mass shootings are defined here as incidents in which a shooter killed four or more people for reasons unrelated to domestic violence, robbery, or gangs.

This timeline charts 91 mass shootings since 1982, using data compiled by Mother Jones. It is a narrow data set, limited to what could be described as rampage-style events: incidents in which a shooter killed four or more people for reasons unrelated to domestic violence, robbery, or gangs. Most of these events happened in public places and attracted widespread media attention.

As the frequency of these events has increased, so has the severity of those with the highest body counts.

After the 1991 Luby’s massacre in Killeen, Texas, claimed 23 lives, it remained the deadliest shooting on record for more than 15 years, until 32 people were killed in the 2007 Virginia Tech shooting in Blacksburg, Virginia.

After Virginia Tech, nine years passed before last year’s Pulse nightclub shooting, in which 49 people were killed. Then, on Sunday, came Las Vegas.

The analysis also shows a growing frequency of mass killings with high victim counts. In the past decade, eight individual shootings claimed 10 or more lives. There were only six such events in the previous quarter century.