fall off vs fulfill

fall off

verb
  • To become detached or to drop from. 

  • 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. 

fulfill

verb
  • To satisfy, carry out, bring to completion (an obligation, a requirement, etc.). 

  • To emotionally or artistically satisfy; to develop one's gifts to the fullest. 

  • To package, distribute, or ship goods. 

  • To obey, follow, comply with (a rule, requirement etc.). 

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