head for the hills vs skedaddle

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. 

skedaddle

verb
  • To move or run away quickly. 

  • To spill; to scatter. 

noun
  • The act of running away; a scurrying off. 

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