coup de grâce vs quietus

coup de grâce

noun
  • A final blow or shot given to kill a wounded person or animal. 

  • A remarkable finishing action. 

quietus

noun
  • Death. 

  • Final settlement (e.g., of a debt). 

  • A stillness or pause; something that quiets or represses; removal from activity. 

How often have the words coup de grâce and quietus occurred in a corpus of books? (source: Google Ngram Viewer )