(Reuters) - The shooting at a suburban Denver high school on Tuesday was the 1,369th incident in the United States since 1970, according to the K-12 School Shooting Database maintained by the Naval Postgraduate School’s Center for Homeland Defense and Security.

The research project documents each time a gun is fired at a school, a bullet hits school property or a gun is brandished in a hostile incident.Colorado has experienced two of the most egregious mass shootings, including the Columbine High School massacre that killed 13 people in 1999 and the 2012 Aurora cinema shooting that killed 12.

In terms of school shootings, however, the state ranks 34th per capita when including the District of Columbia, with 3.16 school shootings per one million residents.

The jurisdictions with the highest rates of school shootings per one million people since 1970 are:

1. District of Columbia, 32.74

2. Alaska, 13.56

3. Louisiana, 9.66

4. Delaware, 8.27

5. Alabama, 7.77

The states with the lowest rates of school shootings per one million people since 1970 are:

51. New Jersey, 1.12

50. Idaho, 1.14

49. North Dakota, 1.32

48. Maine, 1.49

47. West Virginia, 1.66

The states with the highest number of school shootings overall since 1970 are:

1. California, 158

2. Texas, 133

3. Florida, 90

4. Michigan, 67

5. Illinois, 64

The states with the lowest number of school shootings since 1970 are:

51. North Dakota, 1

47. Wyoming, 2

47. Vermont, 2

47. Maine, 2

47. Idaho, 2

SOURCE: K-12 School Shooting Database (www.chds.us/ssdb/)

NOTE: Population figures based on U.S. Census estimates as of July 1, 2018.