cop out vs opt 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. 

opt out

verb
  • To choose not to participate in something. 

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