A history of mass shootings in the United States

Fourteen people were killed and 17 wounded in a mass shooting at the Inland Regional Center in San Bernardino, Calif. on Wednesday. President Obama remarked on the shooting, saying "the one thing we do know is that we have a pattern now of mass shootings in this country that has no parallel anywhere else in the world."

Below is a timeline of mass shootings in the United States over the past 20 years. We have chosen to remove the names of the shooters in these incidents out of respect for the victims.

October 1, 2015: Umpqua Community College shooting

Ten people were killed and seven wounded when a gunman opened fire at Umpqua Community College in Roseburg, Ore.

July 16, 2015: Chattanooga military shooting

Four Marines and a Navy sailor were killed and two others were injured when a gunman opened fire at two military-related buildings in Tennessee.

June 17, 2015: Charleston church shooting

Nine people were were killed when a 21-year-old man opened fire on bible study attendees at Emanuel African Methodist Episcopal Church in Charleston, S.C.

Oct. 24, 2014: Marysville Pilchuck High School shooting

Four people were killed when a student opened fire at the Washington school before turning the gun on himself.

Sep. 16, 2013: Washington Navy Yard shooting

Twelve people were killed and three injured when a gunman opened fire inside the military base before he was fatally wounded by police.

June 7, 2013: Santa Monica College shooting

Five people were killed and four others wounded when a gunman opened fire at the school's library. The shooter was killed by responding police officers.

Dec. 14, 2012: Sandy Hook Elementary School shooting

Twenty-six people were killed when a gunman opened fired at the elementary school in Sandy Hook, Conn. He also shot and killed his mother and later killed himself.

September 27, 2012: Minneapolis workplace shooting

Six people were killed and two injured when a gunman opened fire at Accent Signage Systems in Minneapolis before taking his own life.

Aug. 5, 2012: Wisconsin Sikh temple shooting

Six people were killed and four wounded when a man opened fire at a Sikh temple in Oak Creek, Wis. The gunman committed suicide after he was shot by a responding officer in the stomach.

July 20, 2012: Aurora theater shooting

Twelve people were killed and 70 injured when a gunman entered the Century 16 movie theater in Aurora, Colo. and opened fire on the crowd during opening night of The Dark Knight Rises. The shooter was convicted in July 2015 and sentenced to life in prison without parole.

May 30, 2012: Seattle cafe shooting

Six people were killed and one injured when a gunman opened fire on a Seattle cafe before turning the gun on himself.

Apr. 2, 2012: Oikos University shooting in Oakland, Calif.

Seven people were killed and three wounded when a man opened fire at the school. The accused shooter was later determined to be unfit for trial.

Feb. 22, 2012: Atlanta spa killings

Four people were killed when a gunman opened fire at a Korean spa just outside of Atlanta before turning the gun on himself.

Oct. 12, 2011: Seal Beach shooting

Eight people were killed when a man opened fire at the Salon Meritage hair salon in Seal Beach, Calif.

Sep. 6, 2011: IHOP shooting

Four people were killed and seven injured when a man opened fire at an IHOP restaurant in Carson City, Nev. The shooter later died from a self-inflicted gunshot wound.

Nov. 29, 2009: Lakewood, Wash. police officer shooting

Four police officers were killed when a gunman entered a Washington coffee shop and opened fire. The gunman was later killed by police after a two-day manhunt.

Nov. 5, 2009: Fort Hood shooting in Texas

Thirteen soldiers and civilians were killed and more than two dozen wounded when a gunman walked into the Soldier Readiness Processing Center at Fort Hood, Texas and opened fire. The Army psychiatrist was convicted on 13 counts of premeditated murder and 32 counts of attempted premeditated murder.

Apr. 3, 2009: Binghamton shootings

Thirteen people were killed and four wounded when a gunman opened fire at the American Civic Association immigration center in Binghamton, N.Y. before committing suicide.

Mar. 29, 2009: Carthage nursing home shooting

Eight people were killed and three injured when a man opened fire at a nursing home in Carthage, N.C.

Mar. 10, 2009: Geneva County massacre in Alabama

Ten people were killed, including the shooter's mother and four other relatives, and the wife and child of a local sheriff's deputy. The gunman then killed himself.

June 25, 2008: Atlantis Plastics shooting

Five people were killed when a gunman opened fire at the Atlantis Plastics factory in Henderson, Ky. before turning the gun on himself.

Feb. 14, 2008: Northern Illinois University shooting

Five people were killed and 21 injured when a gunman opened fire at the Dekalb, Ill. college and then took his own life.

Feb. 7, 2008: Kirkwood, Mo. City Council shooting

Six people were killed and one injured when a man opened fire at Kirkwood City Hall. The gunman was then shot and killed by police.

Dec. 5, 2007: Westroads Mall shooting

Eight people were killed and six injured when a gunman opened fire at the Omaha, Neb. mall before turning the gun on himself.

Apr. 16, 2007: Virginia Tech shooting

Thirty-two people were killed and 17 wounded when a student opened fire at the Virginia Tech campus in Blacksburg, Va. The shooter then killed himself.

Feb. 12, 2007: Salt Lake City mall shooting

Five people were killed and four injured when a 32-year-old gunman opened fire at the Trolley Square Mall in Salt Lake City, Utah. The shooter took his own life.

Oct. 2, 2006: West Nickel Mines School shooting

Five people were killed and five injured when a man opened fire at a one-room schoolhouse in the Amish community of Nickel Mines in Pennsylvania before taking his own life.

Mar. 25, 2006: Massacre in Seattle's Capitol Hill neighborhood

Six people were killed and two injured when a 28-year-old man entered a party and opened fire. The gunman then killed himself.

Jan. 30, 2006: Goleta postal facility shootings

Seven people were killed when a a former U.S. Postal Service employee opened fire at a a postal facility in Goleta, Calif. The woman then took her own life.

Mar. 21, 2005: Red Lake Indian Reservation massacre

Nine people were killed and five injured when a student at Red Lake Senior High School killed his grandfather and his grandfather's girlfriend at his home before opening fire at the school in Red Lake, Minn. The shooter then took his own life.

Mar. 12, 2005: Wisconsin church shooting

Seven members of the Living Church of God in Brookfield, Wis. were shot and killed by a gunman who took his own life.

Dec. 8, 2004: Damageplan concert shooting

Four people were killed at a Damageplan concert in Columbus, Ohio when a former U.S. Marine opened fire. The gunman was later killed by police.

July 8, 2003: Lockheed Martin shooting

Six people were killed and eight injured when an employee opened fire at a Lockheed plant in Meridian, Miss. before taking his own life.

Feb. 5, 2001: Navistar shooting

Four people were killed when a gunman opened fire at the Navistar plant in Melrose Park, Ill. before taking his own life.

Dec. 26, 2000: Edgewater Technology shooting

Seven people were killed when an employee at Edgewater Technology in Wakefield, Mass opened fire on his coworkers.

Dec. 30, 1999: Tampa hotel shooting

Five people were killed and three were injured when a gunman opened fire on his colleagues at Radisson Bay Harbor Inn in Tampa, Fla.

July 27-29, 1999: Atlanta spree shootings

Twelve people were killed by a gunman over the course of three days, including the shooter's wife and two children. The man committed suicide after being cornered by police.

Apr. 20, 1999: Columbine High School shooting

Twelve students and a teacher were killed and 26 others wounded when two Columbine High School students opened fire at the Littleon, Colo. school before killing themselves.

May 21, 1998: Thurston High School shooting

Four people were killed when an expelled student opened fire at the Springfield, Ore. high school.

Mar. 24, 1998: Westside Middle School shooting

Five people were killed when two middle school students opened fire at Westside Middle School in Arkansas.

Mar. 6, 1998: Connecticut Lottery shooting

Four people were killed when a lottery worker opened fire on four of his coworkers in Newington, Conn.

Dec. 18, 1997: Caltrans shooting

Four people were killed when a transportation worker opened fire at a Caltrans maintenance yard in Orange, Calif. before taking his own life.

Sep. 15, 1997: R.E. Phelon Company shooting

Four people were killed when a former employee opened fire at the R.E. Phelon Company in Aiken, S.C.

Feb. 9, 1996: Fort Lauderdale shooting

Five people were killed when a gunman opened fire on coworkers in Fort Lauderdale, Fla.

Apr. 13, 1995: Walter Rossler Company shooting

Five people were killed when a gunman opened fire on his former coworkers at Walter Rossler Company in Corpus Christi, Texas before taking his own life.

**For the purpose of this story, a "mass shooting" is defined as one with four or more victims.

The Associated Press and Mother Jones contributed to this report.