introduce vs kick off

introduce

verb
  • To bring (something) into practice. 

  • To cause (someone) to be acquainted (with someone else). 

  • To add (something) to a system, a mixture, or a container. 

  • To make (something or someone) known by formal announcement or recommendation. 

kick off

verb
  • To suddenly become more active. 

  • To make the first kick in a game or part of a game. 

  • To start; to launch. 

  • To shut down or turn off suddenly. 

  • To force the weaning of a bovine cow's calf by restricting the calf's access to its mother's udders. Used figuratively or literally. 

  • To be overcome with anger, to start an argument or a fight. 

  • To dismiss; to expel; to remove from a position. 

  • To have a fight or argument start. 

  • To die or quit permanently. 

How often have the words introduce and kick off occurred in a corpus of books? (source: Google Ngram Viewer )