linger vs persist

linger

verb
  • To remain alive or existent although still proceeding toward death or extinction; to die gradually. 

  • To consider or contemplate for a period of time; to engage in analytic thinking or discussion. 

  • To stay or remain in a place or situation, especially as if unwilling to depart or not easily able to do so. 

persist

verb
  • To cause to persist; make permanent. 

  • To go on stubbornly or resolutely. 

  • To repeat an utterance. 

  • To continue to exist. 

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