fall off vs propagate

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. 

propagate

verb
  • To cause to take effect on all relevant devices in a network. 

  • To spread from person to person; to extend the knowledge of; to originate and spread; to carry from place to place; to disseminate. 

  • To produce young; to be produced or multiplied by generation, or by new shoots or plants. 

  • To cause to spread to extend; to impel or continue forward in space. 

  • To cause to continue or multiply by generation, or successive production. 

  • To generate; to produce. 

  • To take effect on all relevant devices in a network. 

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