I find that hard to believe. It sounds like the author's trying to minimize the tragedy. She's pretty young. Maybe the possibility of searching through microfiche newspaper archives wasn't the first thing that popped into her mind.

Now I have to take that back. Here's another of her articles that goes into much more detailed data: Mass shootings in America are a serious problem -- and these 9 charts show just why.

From that article:
There's your American exceptionalism right there.