fly the coop vs slide off

fly the coop

verb
  • To depart hastily or unannounced; to escape or flee. 

  • To escape from a pen or similar enclosure. 

slide off

verb
  • To leave a place, a meeting, etc., without being noticed; to slip away, slip off. 

  • Used other than figuratively or idiomatically: see slide, off. 

How often have the words fly the coop and slide off occurred in a corpus of books? (source: Google Ngram Viewer )