flee vs pull back

flee

verb
  • To run away; to escape. 

  • To escape from. 

  • To disappear quickly; to vanish. 

pull back

verb
  • To retreat. 

  • To pass (the ball) into a position further from the attacking goal line. 

  • Used other than figuratively or idiomatically: see pull, back. 

  • To score when the team is losing. 

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