More than 1 shooting per day in 2015 in US

Police officers conduct a manhunt after a mass shooting in San Bernardino, California December 2, 2015. © Mike Blake
The mass shooting in San Bernardino, California, was the deadliest gun violence episode in 2015 in the US, but far from being the only one.

At least 40 other cases with at least four fatalities each, which is the FBI definition for a mass shooting, was reported in the US this year, according to shootingtracker.com, a website that aggregates gun violence data reported by the media.

Under a broader definition used by the site, which covers all cases with at least four people injured or killed by gunfire, including perpetrator or perpetrators, 355 mass shootings happened in 2015. Two, including the rampage in San Bernardino, happened on Wednesday.

Here are some other cases from this year.

February, Missouri: 8 killed, including shooter, 1 injured

On February 27 a gunman went on a door-to-door shooting spree in Missouri before killing himself. The police reported that the rampage may have been triggered by the perpetrator finding his mother dead in her home from apparent natural causes.

Police tape surrounds one of the crime scenes where gunman, Joseph Jesse Aldridge, killed seven people on Thursday night in Tyrone, Missouri February 27, 2015. © Kate Munsch

May, Texas: 9 killed, 18 injured

On May 17, several rival biker gangs clashed in a brawl at a restaurant in Waco, Texas, which quickly escalated into a gun battle.

Police escort a man at the scene of a shooting in Waco, Texas, in this handout photo provided by the Waco Police Department on May 17, 2015. © /Waco Police Department

June, South Carolina: 9 killed

A shooting at the historic Emanuel African Methodist Episcopal Church in Charleston, South Carolina, claimed nine lives on June 17. The perpetrator was later apprehended and identified as a self-proclaimed white supremacist. The crime received worldwide publicity and triggered a public debate on racism in the US.

Patricia Bailey prays at a makeshift memorial outside the Emanuel African Methodist Episcopal Church in Charleston, South Carolina June 20, 2015, three days after a mass shooting which left nine people dead during a bible study at the church. © Brian Snyder

August, Texas: 8 killed

A man with a history of abusing his former girlfriend gunned down the woman, her husband and six children on August 8 shortly before police arrived on the scene.

The second of eight bodies is loaded into the coroner's truck at the scene of a shooting in which eight people were killed, in Houston, Texas August 9, 2015. © Daniel Kramer

October, Oregon: 10 killed, including the shooter, 7 injured

A man went on a gun rampage on October 1 at the campus of Umpqua Community College in southern Oregon. The shooter killed an assistant professor and eight students before engaging in a short shootout, with police responding to the violence and taking his life.

People take part in candle light vigil following a mass shooting at Umpqua Community College in Roseburg, Oregon October 1, 2015. © Steve Dipaola