jawbreaker vs knuckle sandwich

jawbreaker

noun
  • A hard blow to the side of the face. 

  • A large, extremely hard, boiled candy, typically spherical. 

  • A long, hard-to-pronounce word. 

knuckle sandwich

noun
  • A punch to the face, especially to the mouth. 

How often have the words jawbreaker and knuckle sandwich occurred in a corpus of books? (source: Google Ngram Viewer )