There were at least 3,380 threats against K-12 schools recorded in the 2017-18 school year, a 62 percent increase from threats in the 2016-17 school year, according to The Educator’s School Safety Network (ESSN).

https://www.securitymagazine.com/articles/89457-threats-of-school-violence-increased-62-percent-in-2017-18