From one of the links Cindi posted:
"Active shooter incidents" at elementary/secondary schools, 2000-2009: 16, resulting in 24 deaths.
"Active shooter incidents" at elementary/secondary schools, 2010-2017: 21, resulting in 43 deaths. (nb this over a shorter period and does not include Parkland)
This is less a point about gun control as a point about posting links and bullshitting about what's in them, thus making me feel obligated to find the relevant charts in a 268 page pdf.