По данным Los Angeles Times, с 14 декабря 2012 года, когда было расстреляно 20 детей и шестеро взрослых в школе Сэнди Хук, штат Коннектикут, в США имело место 142 инцидента со стрельбой в школах. Таким образом, указывает газета, в школьных учреждениях США стреляют примерно раз в неделю. При этом в статистику не вошли случаи, когда на территорию учебного заведения было пронесено огнестрельное оружие, но оно не было применено.
Издание (LATimes) приводит интерактивную карту, скриншот которой вы можете видеть ниже.

[ИЗУЧАЮЩИМ АНГЛИЙСКИЙ]
A tragic incident took place on December 14 (fourteenth), 2012 (twenty twelve) at Sandy Hook Elementary School in Newtown, Connecticut.
On that day 20 children and six adults were killed in a school shooting incident.
Since that day there have been 142 school shootings in the U.S.
An incident is classified as school shooting if a firearm was fired inside a school building or on campus.
Naturally, cases when guns were brought into school and not fired are not in the statiscics of school shootings.
(adapted text)
In the original:
There have been 142 school shootings in the U.S. since 20 children and six adults were killed at Sandy Hook Elementary School in Newtown, Conn. (Connecticut) on Dec. 14, 2012. Incidents were classified as school shootings when a firearm was discharged inside a school building or on campus, as documented in news accounts. Incidents in which guns were brought into schools but not fired (...) were not included.
[ИСТОЧНИК: LOS ANGELES TIMES]
Since Sandy Hook, there has been nearly one school shooting a week
Journal information