I'm still not sure how they are measuring that. Is it number of incidents? Number of victims? Something else?
That number is pulled from FBI data which is focused on criminal activity rather than victims, so yes, per incident. However, the overall trend is consistent by every metric I've seen.
In strict numbers
by the Department of Justice,
There were 11,101 firearm homicides in 2011, down by 39% from a high of 18,253 in 1993
From Pew Research
Compared with 1993, the peak of U.S. gun homicides, the firearm homicide rate was 49% lower in 2010, and there were fewer deaths, even though the nation’s population grew. The victimization rate for other violent crimes with a firearm—assaults, robberies and sex crimes—was 75% lower in 2011 than in 1993. Violent non-fatal crime victimization overall (with or without a firearm) also is down markedly (72%) over two decades.
Note that it's not just for incidents with a firearm, though. Nor does it look like the absolute number of guns in the US dropped.
The frustrating thing for me, because it demonstrates a consistent and deliberate theme of misinformation from our news sources and politicians to create tension and panic, is this bit:
Despite national attention to the issue of firearm violence, most Americans are unaware that gun crime is lower today than it was two decades ago. According to a new Pew Research Center survey, today 56% of Americans believe gun crime is higher than 20 years ago and only 12% think it is lower.
Crime is cut in half, but somehow nearly five times as many people think it's up compared to those who know the truth. And that belief is so deep that, as we see in this thread, the initial response is to disbelieve the hard numbers.
For more craziness: the trend in schools is even more pronounced
School violence in the U.S. reached a peak in 1993, according to the National Center for Education Statistics. That year, there were 42 homicides by students in total, as well as 13 "serious violent crimes" — rape, sexual assault, robbery and aggravated assault — per 1,000 students at primary and secondary schools. By 2010, the latest figures available, those numbers had decreased to two homicides and four violent crimes per 1,000 students.
Total homicides in primary and secondary schools:
Note that Columbine, typically seen as the start of our current mass killing era, was in '99 - after which there's actually a marked decade of significantly reduced violence. The numbers are certainly up in the last couple of years, but I haven't found any raw numbers for '13 and after.
It may come as no surprise that the 24-hour news cycle gets much of the blame for perpetuating a false notion about the extent of school violence.
I also think they deserve a lot of the blame for causing it, but that's opinion
To be clear, I'm not saying there isn't a problem - there absolutely is. However, it should be approached with an informed and logical conversation, and the evidence shows that various social programs, most of which aren't very newsworthy, are being very successful at reducing crime and deaths during an era with very little increased gun regulation. We can be an armed and polite society.
On the other hand, most of the deaths from firearms are not murders: they're suicides. While we're fixated on stranger danger, the reality is that you're more likely to do yourself in than be killed by someone else with a gun.
gun suicides now account for six-in-ten firearms deaths
And an article here: Gun Deaths Are Mostly Suicides.
Which, despite the difficulties involved, is a solid argument for finding a way to keep guns away from those suffering dangerous mental illness, primarily by some sort of screening process but also, yes, by finding ways to reduce and control the national arsenal.