cool off vs pull in one's horns

cool off

verb
  • To decrease in temperature, activity, or temper. 

  • To cause to decrease in temperature, activity or temper. 

pull in one's horns

verb
  • To become less impassioned, aggressive, or argumentative; to exercise restraint; to yield or capitulate. 

How often have the words cool off and pull in one's horns occurred in a corpus of books? (source: Google Ngram Viewer )