cool off vs dwindle

cool off

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

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

dwindle

verb
  • To decrease, shrink, diminish, reduce in size or intensity. 

  • To lessen; to bring low. 

  • To break up or disperse. 

  • To fall away in quality; degenerate, sink. 

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