head for the hills vs peg it

head for the hills

verb
  • To go to a safe place; to seek refuge; to flee. 

  • To travel to a higher elevation, especially to a rural region on vacation. 

peg it

verb
  • To run away; to leg it; to scarper. 

  • To die. 

How often have the words head for the hills and peg it occurred in a corpus of books? (source: Google Ngram Viewer )