keep going vs persist

keep going

verb
  • To continue functioning. 

  • To proceed; to make progress, physically or figuratively. 

  • To see that (a person) is continually supplied with something, or that they can progress or carry on. 

persist

verb
  • To continue to exist. 

  • To go on stubbornly or resolutely. 

  • To repeat an utterance. 

  • To cause to persist; make permanent. 

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