A Look at Mass Shootings in the United States

Dec. 14, 2012 — -- If you've been following the news cycle, it seems like every month or so we hear of a horrific tragedy like today's in Newtown, Conn., where police are reporting that at least 27 people were killed -- 20 of them children -- in a shooting at the Sandy Hook Elementary School. But are mass shootings actually on the rise?

When you look at a list of mass shootings in the last 30 years, in which a single gunman killed at least four people, this year does have the highest number of incidents with six mass shooting incidents excluding today's tragedy, according to a list compiled this year by Mother Jones. The Aurora movie theater shooting in Colorado, the Sikh shooting in Wisconsin, and the Seattle cafe shooting are among this year's massacres.

And the last few years have also had slightly higher incidents than those in the past three decades. Six of the 12 deadliest shootings have taken place since 2007, and Newton will rank second on that list, according to a report done by The Washington Post.

In 2011 there were three such tragedies, including the Tucson shooting which injured Congresswoman Gabrielle Giffords (D-Ariz.). In 2010, there was one killing classified as a mass shooting. And in 2009 there were four tragedies, among them, the Fort Hood massacre in Texas, in which Army psychiatrist Nidal Malik Hasan, opened fire at a U.S. Army base.

Between the years of 2000 and 2004, however, there was either one mass-shooting incident or no incident each year. In 1999, the U.S. experienced five incidents, including the devastating Columbine massacre. And up until the 1970's there were only one or two "spree-killings" in the 20th century, according to David Brooks' estimates for The New York Times. Still, criminologist James Alan Fox from Northeastern University has said we can't definitively say this year has seen a spike in mass killings.

"Without minimizing the pain and suffering of the hundreds who have been victimized in senseless attacks, the facts say clearly that [there] has been no increase in mass killings, and certainly no epidemic," Fox wrote in a column for Boston.com in August. "Occasionally, we have witnessed short-term spikes with several shootings clustering close together in time. In the 1980s, we had a flurry of postal shootings, and the 1990s included a half dozen schoolyard massacres. Other than the copycatting reflected in these cases, the clustering of mass murders is nothing more than random timing and sheer coincidence," he wrote.

Still, the details of each case are certainly troubling. In 49 of the 61 cases the gunmen obtained the weapons legally, and the majority of those weapons used were semi-automatic. Forty three of the 61 killers were white males, and one was a female, according to the list. The murders happened in 30 states around the country, and just under half of them were school or workplace shootings, according to The Mother Jones report.

Disturbingly, there have only been three years since 1982, according to the Mother Jones data, during which the United States didn't experience a mass shooting.

Click here to see Mother Jones' full breakdown and virtual map of the incidents.