Data on mass shootings is hard to track, mainly because not every agency agrees on the exact definition of what a public mass shooting is.
But numbers provided to NBC 7 Investigates by the non-partisan think tank The Violence Project show 1,145 people were killed in 158 shootings since 1966.
The organization is building a database of every mass shooting, and the suspects behind shootings where four or more people were killed in a public place.
News of the shootings in El Paso, Texas and Dayton, Ohio have civil rights community worried.
“I am more concerned now than I was 20 years ago,” said San Diego civil rights attorney James McElroy. McElroy also sits on the board for the Southern Poverty Law Center.
He says mass shootings by white extremists are, “Undoubtedly on the rise,” and he attributes it partially to what he calls the "mainstreaming of hate.”
“When you have the leaders of your country saying things that no leaders of this country have ever said before and you wonder how much that's enabling or even encouraging,” said McElroy.
In 2019, The Violence Project report five mass shootings in Dayton, Ohio; El Paso, Texas; Virginia Beach, Virginia; Aurora, Illinois and Sun Trust Bank, Florida. Their list doesn't include the shooting in Gilroy, California or the synagogue shooting here in Poway, where less than four people were killed.
As of now, only the El Paso shooting is recorded as hate motivated. Three others they tracked this year were workplace shootings.
Looking at their data, The Violence Project predicts a nearly four percent increase in mass shootings a year.
Copycat shootings are something McElroy worries about.
“So yes, definitely it concerns me that some of these shooters will be copied and that is going to require greater diligence on our part,” McElroy said.
The Violence Report is releasing its full database findings later this year. They say hate motivated mass shootings make up only about eight percent of the total incidents where other grievances, like those tied to a workplace, are more common.