forget vs persist

forget

verb
  • To unintentionally leave something behind. 

  • To lose remembrance of. 

  • To unintentionally not do, neglect. 

  • To cease remembering. 

  • Euphemism for fuck, screw (a mild oath). 

persist

verb
  • To go on stubbornly or resolutely. 

  • To repeat an utterance. 

  • To cause to persist; make permanent. 

  • To continue to exist. 

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