exorbitant vs highway robbery

exorbitant

adj
  • Exceeding proper limits; excessive or unduly high; extravagant. 

highway robbery

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

  • Said of excessive or exorbitant prices. 

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