There have been at least 50 school shootings in the United States so far this year, as of September 19. Thirteen were on college campuses, and 37 were on K-12 school grounds. The incidents left 24 people dead and at least 66 other victims injured, according to CNN’s analysis of events reported by the Gun Violence Archive, Education Week and Everytown for Gun Safety.
https://www.cnn.com/us/school-shootings-fast-facts-dg/index.html
What about the OP is ambiguous that they mean 50 since the start of this year?