INDIANAPOLIS — A mass shooting at a medical complex in Tulsa, Oklahoma, is the latest in a series of mass killings that have claimed 88 lives since the beginning of the year.

An Associated Press database shows there have been 15 mass killings in a total of nine states across the United States since the beginning of 2022. Since 2006, there have been 495 mass killings, resulting in the loss of 2,604 lives.

Nearly every state has been impacted by mass killings since 2006, with the exception of New Hampshire, Rhode Island, and Hawaii. California has experienced the most mass killings with 56 incidents resulting in a total of 287 deaths since 2006.

The most victims in a single mass killing event happened in Las Vegas, when Stephen Paddock, open fire on concertgoers, killing 60 people.

The database tracks all U.S. homicides since 2006 that involve four or more people that were killed over a period of 24 hours regardless of weapon, location, victim-offender relationship, or motive. The victim count does not include the offender.

The 24-hour time frame was chosen to eliminate merging spree killers, who kill multiple victims in quick succession in different locations or incidents, and to satisfy the traditional requirement of occurring in a “single incident.”

Of the mass killings, the vast majority have shootings as the primary manner of death. According to the data, 388 mass killing incidents have occurred involving shootings since 2006, resulting in 2,906 deaths.

While public mass killings like the Uvalde school shootings gather a lot of attention, an analysis of mass killing data shows only 20% of mass killing incidents happen in public places. The majority of mass killings are family-related, where an offender kills their own relatives or the relatives of a romantic partner.

There are also many mass killings that are primarily motivated by the desire to commit some other crime such as robbery, drug trafficking, gang warfare, or sexual assault.

The majority of mass killings ended with the offender killing themselves after committing the mass killing. Of the 608 offenders, 455 committed suicide.

In response to the mass shootings in Tulsa, Oklahoma; Uvalde, Texas and Buffalo, New York, President Joe Biden is attempting to increase the pressure on Congress to pass stricter gun limits after such efforts failed in the wake of past violence.

Any major action is still a long shot. While the Senate approved a modest measure to encourage compliance with background checks after a 2017 church mass shooting in Texas and one in Parkland, Florida, the following year, no major legislation cleared the chamber following the devastating massacre of 20 children at Sandy Hook Elementary School in 2012.

The Associated Press contributed to this report.