dwindle vs fall off

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. 

fall off

verb
  • To diminish in size, value, etc. 

  • To fall into sin; stray. 

  • To change the direction of the sail so as to point in a direction that is more down wind; to bring the bow leeward. 

  • To become detached or to drop from. 

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