Washington Post: So far, there have been more U.S. mass shootings than days in 2015

2015 snapshot: Thursday is the 337th day of the year, and to date, there have been 355 mass shootings

According to the Washington Post's Wonkblog, which has been keeping a running tally on U.S. mass shootings, to date in 2015, there have been more mass shootings than days in the year.

Last week alone, there were at least 12 mass shootings in the U.S., counting the Colorado Springs Planned Parenthood clinic shooting, Wonkblog reports. 

On Wednesday, there were two reported mass shootings -- the San Bernardino shooting and a mass shooting in Savannah, Ga.

A mass shooting, according to the blog, is defined as "incidents in which four or more people, including the gunman, are killed or injured by gunfire."

Read the full Washington Post article here.

Via Reuters, below are some of the worst shooting incidents in recent years, ranked by the number of dead, including the gunman:

Virginia Tech 

April 16, 2007 - A gunman slaughters 32 people and kills himself at Virginia Tech, a university in Blacksburg, Virginia. 

Sandy Hook 

Dec. 14, 2012 - A gunman kills 20 children and six adults and himself at Sandy Hook Elementary School in Newtown, Connecticut.

Columbine 

April 20, 1999 - Two heavily armed teenagers go on a rampage at Columbine High School in Littleton, Colorado, shooting 12 students and a teacher to death and wounding more than 20 others before taking their own lives.

Immigration center

April 3, 2009 - A Vietnamese immigrant opens fire at an immigrant services center in Binghamton, New York, killing 13 people and wounding four. He then kills himself. 

Fort Hood

Nov. 5, 2009 - A gunman opens fire at Fort Hood, a U.S. Army base in Texas, killing 13 people and wounding 32. The gunman, an Army major and psychiatrist, was sentenced to death for the rampage.

Washington Navy Yard 

Sept. 16, 2013 - A former Navy reservist working as a government contractor kills 12 people at the Washington Navy Yard. Eight people are injured. The gunman was killed by police. 

Colorado movie theater

July 20, 2012 - A masked gunman kills 12 people and wounds 70 when he opens fire on moviegoers at a midnight premiere of the Batman film "The Dark Knight Rises" in Aurora, a Denver suburb. A former graduate student is sentenced to life in prison for the rampage. 

Washington, D.C., snipers 

October 2002 - Two men ambush 13 people, killing 10 of them, in a string of sniper-style shootings that terrorize the Washington area.

Oregon college

Oct. 1, 2015 - A gunman storms onto the campus of Umpqua Community College in southwest Oregon and opens fire, killing nine people and wounding seven others before police shoot him to death.

Charleston church

June 17, 2015 - A white supremacist gunman kills nine black churchgoers during a Bible study session at a historic, predominantly black church in Charleston, South Carolina. The suspect is awaiting trial. 

Waco bikers
May 17, 2015 - Rival motorcycle gangs kill nine at a restaurant in Waco, Texas. More than 170 people are arrested.

Grandfather kills family

Sept. 18, 2014 - Man kills his daughter and six grandchildren in Bell, Florida, and then kills himself. 

Oikos University

April 2, 2012 - A former student kills seven students at Oikos University, a small Christian school in Oakland, California. The suspect is awaiting trial.

Sikh temple

Aug. 5, 2012 - A white supremacist walks into a Sikh temple in Oak Creek, Wisconsin, shoots six worshippers and wounds four others, including a policeman. The gunman kills himself after being shot by a police officer.

Florida apartment

July 26, 2013 - A man goes on a shooting spree at an apartment complex in Hialeah, Florida, killing six people. The shooter is killed by police. 

Congresswoman assassination attempt 

Jan. 8, 2011 - Then-U.S. Rep. Gabrielle Giffords is the target of an assassination attempt by a gunman in Tucson, Arizona, in which six people are killed and 13, including Giffords, are wounded.

Planned Parenthood

Nov. 27, 2015 - A gunman storms a Planned Parenthood health clinic in Colorado Springs, Colorado, killing three people and wounding nine. Police arrest the gunman.

Television journalists

Aug. 26, 2015 - A reporter and a cameraman are fatally ambushed by a former employee of their Roanoke, Virginia, television station while they are interviewing a woman on live TV. The woman is wounded. The gunman later kills himself as police pursue him on a highway hours after the shooting.