By Saeed Ahmed and Christina Walker, CNN

(CNN) -- We're only 20 weeks into 2018, and there have already been 22 school shootings where someone was hurt or killed. That averages out to more than 1 shooting a week.

The parameters CNN followed in this count are:

• A shooting that involved at least one person being shot (not including the shooter)

• A shooting that occurred on school grounds

• We included grades K through college/university level

• We included gang violence, fights and domestic violence

• We included accidental discharge of a firearm as long as the first two parameters are met

May 18: Santa Fe, Texas

Someone opened fire at Santa Fe High School, resulting in multiple fatalities, two law enforcement sources told CNN.

May 11: Palmdale, California

A 14-year-old boy went to Highland High, his former school, and began shooting a semiautomatic rifle shortly before classes were scheduled to begin, officials said. A 15-year-old boy was struck in the shoulder.

April 20: Ocala, Florida

A 17-year-old student at Forest High School was shot in the ankle shortly before students were to walk out as part of a national protest against gun violence.. The suspect was a 19-year-old former student.

April 12: Raytown, Missouri

A man was shot in the stomach in the parking lot of Raytown South Middle School during a track meet.

April 9: Gloversville, New York

A student shot another student with a BB gun in Gloversville Middle School.

March 20: Lexington Park, Maryland

An armed student shot two others at Great Mills High School before a school resource officer fired a round at the shooter. The shooter was killed. One of the students, 16-year-old girl Jaelynn Willey, was taken off life support two days later.

March 13: Seaside, California

A teacher accidentally discharged a gun during a public safety class at Seaside High School, injuring a student.

March 8: Mobile, Alabama

One person was hospitalized after a shooting at an apartment building on the campus of the University of South Alabama.

March 7: Birmingham, Alabama

One student was killed and another critically wounded after an accidental shooting during dismissal time at Huffman High School. Police wouldn't elaborate further.

March 7: Jackson, Mississippi

A student was shot inside a dormitory at Jackson State University. His injuries were not life-threatening.

March 2: Mount Pleasant, Michigan

Two people were shot to death at a dormitory on the campus of Central Michigan University. The victims were not students and police think the incident stemmed from a domestic situation.

February 27: Norfolk, Virginia

A student at Norfolk State University was shot from an adjacent dorm room while he was doing homework. He was not seriously injured.

February 27: Itta Bena, Mississippi

A person was shot in a rec center at Mississippi Valley State University. Police said the person was not a student and the injury was not life-threatening.

February 24: Savannah, Georgia

A person was shot on the campus of Savannah State University and taken to a nearby hospital where he later died. Neither the victim nor the shooter were university students, the college said.

February 14: Parkland, Florida

A 19-year-old man gunned down students and staff with a rifle at Marjory Stoneman Douglas High School in Parkland, slaughtering at least 17 unsuspecting students and adults. The shooter, Nikolas Cruz, had been expelled from the high school over disciplinary problems, officials said.

February 9: Nashville

A high school student was shot five times in the parking lot of Pearl-Cohn High School.

February 5: Oxon Hill, Maryland

A high school student was shot in the parking lot of Oxon Hill High. The victim was treated and later released. Police arrested two teens and said they are acquaintances of the victim.

February 1: Los Angeles

A 15-year-old boy was shot in the head and a 15-year-old girl shot in the wrist at Sal Castro Middle School in Los Angeles, officials said. Two other students were grazed by bullets. A 12-year-old girl was booked for negligent discharge of a firearm in that shooting, which was considered "unintentional," Los Angeles police said.

January 31: Philadelphia

A fight led to a shooting in the parking lot of Lincoln High School, fatally wounding a 32-year-old man.

January 23: Benton, Kentucky

A 15-year-old student shot 16 people -- killing two other 15-year-olds -- at Marshall County High School, authorities said. The student faces two charges of murder and 12 counts of first degree assault.

January 22: Italy, Texas

A 15-year-old student was wounded in a shooting at a high school in Italy, Texas, authorities said. The suspect, also 15, was quickly apprehended.

January 20: Winston Salem, North Carolina

A Winston-Salem State University football player, Najee Ali Baker, was shot to death at a party on the campus of Wake Forest University.