started in 1966 my first year of high school  and btw they are pretty much ALL American  Texas Tower shooting of 1966 summary  https://www.britannica.com/summary/Texas-Tower-shooting-of-1966 

 in fact the USA started WAY earlier than that

https://media.spinster.xyz/2616e522a3360780e621636d161fef455228ccb302a37c09eb4493a8b4992eb9.png 

 1940

https://media.spinster.xyz/eab8fb309d464c1b916ac8625e8aaaba7f549c80a0b72fdd23c30eb2636fc033.png 

 THREE HUNDRED EIGHTY NINE SINCE COLUMBINE  https://www.washingtonpost.com/education/interactive/school-shootings-database/ 

 Accelerating in line with the uptake in prescribed medicines 😉