hold on vs persevere

hold on

verb
  • To persist. 

  • To remain loyal. 

  • To grasp or grip firmly. 

  • To keep; to store something for someone. 

  • Wait a short while. 

persevere

verb
  • To persist steadfastly in pursuit of an undertaking, task, journey, or goal, even if hindered by distraction, difficulty, obstacles, or discouragement. 

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