This Google Ngram compares the usage of the words 'gun control', 'gun violence', and 'school shootings' in the American corpus. It is interesting to note that the discussion of gun control is much more common than the discussion of gun violence and school shootings combined.

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The political discussion of gun control started gaining traction after 1965 and led to the passage of the first gun control  legislation, the Gun Control Act of 1968. After passage of this act, it became a mainstay discussion. The first notable school shootings that included multiple victims started around 1976, and continued to rise as these events became more common, peaking in 1999 after the Columbine shootings.