cop out vs hem and haw

cop out

verb
  • To avoid or shirk, either by failing to perform, or by performing in a grossly insufficient, negligent, or superficial manner. 

  • To plead guilty and ask for mercy. 

hem and haw

verb
  • To mumble and procrastinate in one's speech, especially with a reply to a hard question or with voicing a decision on a topical matter; to evade a question, giving vague answers; to equivocate or temporize. 

  • To discuss, deliberate, or contemplate rather than taking action or making up one's mind. 

How often have the words cop out and hem and haw occurred in a corpus of books? (source: Google Ngram Viewer )