Exactly nineteen years ago, 13 people were killed at Columbine High School in Littleton, Colorado. At the time, it was the deadliest high school shooting — and one of the worst mass shootings — in modern U.S. history.

Now it’s not even one of the 10 worst — and students and adults are still dying on our country’s campuses.

As the anniversary of that cruel day in Colorado approached, students from Parkland, Florida, somehow kept school gun violence a central subject of conversation in an overwhelmed nation. We wondered what we could say today that might move the needle on an all-too-often irrational national debate over sensible gun legislation and campus safety. We wondered about all those lives cut short on campuses in the past 19 years. We wondered how many lives that was.

19 Median age of school shooting victims

since April 20, 1999

So we asked writer Abby Hamblin to do some research. Please take the time to read these 223 names. Be sad. Be outraged. They represent everyone killed on an educational campus in the last two decades, starting at Columbine. They are on-campus victims of mass shootings, gang violence or gun incidents, including those in campus housing and at athletic fields. Our list excludes suicides, drive-by shooting victims and people killed on buses or at off-campus events. If we overlooked a name, we apologize. Our intent here was twofold: to honor victims and to urge you to call congressional leaders and school board members and to demand change. A Pew Research Center survey taken after the Feb. 14 Parkland, Florida, shooting found 57 percent of teenagers worry about the possibility of a shooting at their school, and 25 percent are very worried. That's scary in and of itself.

As parents who just want our kids to be safe. As journalists sickened by school shooting coverage. As taxpayers fed up with misplaced budget priorities that overlook common-sense ways to protect our community’s children. As voters incensed Congress does too little. We say, “Enough.”

Starting with Columbine, there have been 85 school shootings. Those shootings have killed 223 people, including students, teachers and staff. That adds up to 11,100 years of life* cut short by gun violence.

* For this calculation, we subtracted each victim's age from his or her life expectancy as determined by the National Center for Health Statistics based on date of birth and gender, then added all those numbers together. We excluded people who lived longer than their life expectancy from our equation.

To demand change from your congressional representatives, tweet at them. To demand change from San Diego school officials, tweet at the district. Tag @sdutIdeas in your tweets, and we’ll collect all of them in a separate post. Thank you. Enough is enough.

Prepared by editorial and opinion director Matthew T. Hall, writer Abby Hamblin, data designer Daniel Wheaton, video producer John Kelley, web developer Ruby Gaviola and designer Gloria Orbegozo.