The report found that there were 41 mass killings in 2019. A mass killing is defined in the report as when four or more people are killed, excluding the perpetrator.

Of the 41 mass killings, 33 were mass shootings. More than 200 people were killed in total from the incidents.

Several mass shootings this year generated attention and renewed debates about gun control legislation. Two mass shootings in the same weekend in El Paso, Texas, and Dayton, Ohio, over the summer were among the worst incidents in 2019.

Other noteworthy mass shootings this year included massacres in Virginia Beach, Va., and Jersey City, N.J.

The AP reported that a majority of the killings involved people who knew one another.

The 41 mass killings were the most in a single year since 2006, when the database began tracking such incidents, though other research dating back to the 1970s shows no other year with as many mass killings. The second-highest number of killings in a year prior to 2019 was 38 in 2006, according to the AP.

Although 2019 had the highest number of incidents, it did not have the highest number of casualties. The 211 people killed in 2019 were eclipsed by the 224 victims in 2017, the year when the deadliest mass shooting in modern U.S. history took place in Las Vegas during a music festival.