palm off vs work off

palm off

verb
  • To sell or dispose of (something) with the intent to deceive; to attempt to pass off a counterfeit or inferior product as genuine. 

work off

verb
  • To end (a debt) by doing labor for the person owed money. 

  • To lose (weight) by doing physical work; to burn off the calories gained from eating something. 

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