highway robbery vs outrageous

highway robbery

noun
  • The act of robbing a traveler on a public road. 

  • Said of excessive or exorbitant prices. 

outrageous

adj
  • Transgressing reasonable limits; extravagant, immoderate. 

  • Shocking; exceeding conventional behaviour; provocative. 

  • Violating morality or decency; provoking indignation or affront. 

How often have the words highway robbery and outrageous occurred in a corpus of books? (source: Google Ngram Viewer )