diminish vs fall off

diminish

verb
  • To make smaller. 

  • To taper. 

  • To disappear gradually. 

  • To take away; to subtract. 

  • To lessen the authority or dignity of; to put down; to degrade; to abase; to weaken; to nerf (in gaming). 

  • To become less or smaller. 

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 diminish and fall off occurred in a corpus of books? (source: Google Ngram Viewer )