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The internet is full of numbers, statistics and clever charts about gun violence in the United States, but not all of them are accurate.

We wanted to take a fresh look at the arguments around the idea of banning "assault weapons" by looking at the time before, during, and after the last federal ban.

In doing so, we also found more context around mass shootings that may inform the debate.

WHAT WE FOUND

The FBI doesn't have a definition for mass shooting, but it does have one for mass murder. It defines mass murder as "four or more victims slain, in one event, in one location."

Congress defines a mass killing as "three or more killings in single incident."

Most outlets seem to use these definitions as a guideline.

For example, Mother Jones defines a mass shooting as one where the attacker(s) kill four or more other people. However, The Gun Violence Archive expands its definition to include people who are injured.

9NEWS decided to look at mass casualty shootings a different way.

Because the incidents driving the debate involve entire crowds or groups being attacked, we chose to focus on incidents in which 10 or more people were wounded in gunfire since 1984.

ASSAULT WEAPONS BAN

The previous federal assault weapons ban was in place from September 1994 until September 2004. It banned certain specific models of guns and guns that had specific features listed in the law.

It also banned ammunition magazines that held more than 10 rounds. However, it let people keep the guns and magazines they already owned, grandfathering in millions of existing weapons and accessories.

We broke down the numbers of attacks and victims in large-scale shootings (with 10 or more people injured) for the decade of the ban-- and the decades just before and after.

Here's what we found:

It's important to note that people debate whether the ban was effective at curbing violence. And dozens of researchers have weighed in with theories about why crime rates dropped in the 1990's and early 2000's.

Those theories include unleaded gasoline, an increase in police, people drinking less and the economy.

MORE CASUALTIES WHEN RIFLES INVOLVED

With a lot of focus on the AR-15 and similar rifles, we broke down the data to screen out events where no rifle was involved.

Our data had about an even split with 28 incidents involving rifles and 24 without.

Despite those similar numbers, the shootings without a rifle counted for 27 percent of the casualties.

The Las Vegas shooting from 2017 accounts for about one third of the rifle injures:

GUNS PURCHASED LEGALLY

Among the large-scale attacks we examined, a pattern emerged when it came to how the shooters got their guns-- 82 percent of the shooters purchased their guns and ammunition legally.

SCHOOL SHOOTINGS

There's been a lot of recent debate over exactly how many school shootings we have in this country.

Fourteen of the shootings on our list happened in schools.

If you expand the list to the more traditional definition of "mass shooting," with four or more people killed, the number increases just slightly to 16 since 1984.

That's about one every other year.

It's a significantly smaller number than the one used by Everytown for Gun Safety. The gun control advocacy group claims there were 18 school shootings since the start of 2018 and 290 since 2013.

The problem with Everytown's number is it includes incidents like this one from Minnesota where a third grader pulled the trigger on a school liaison officer's gun while it was holstered. Nobody was injured, and it doesn't appear that the kid intended to harm anyone.

Or this one from Kansas where a man shot himself in the foot by accident. He went to adjust his sock when the gun holstered to his ankle accidentally discharged during a graduation ceremony.

The problem with using only mass casualty shootings is what happened at a Kentucky high school in January doesn't make the list. In that incident, a 15-year-old student killed two teens and wounded more than a dozen others.