hold on vs persist

hold on

verb
  • To persist. 

  • To remain loyal. 

  • To grasp or grip firmly. 

  • To keep; to store something for someone. 

  • Wait a short while. 

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 hold on and persist occurred in a corpus of books? (source: Google Ngram Viewer )