cop out vs puss out

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. 

puss out

verb
  • To avoid doing something due to cowardice. 

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