extortionate vs worth its weight in gold

extortionate

adj
  • Of, related to, or typifying extortion (“the practice of obtaining money or other property by the use of force or threats”). 

  • Greatly exceeding what is moderate or reasonable; exorbitant. 

worth its weight in gold

How often have the words extortionate and worth its weight in gold occurred in a corpus of books? (source: Google Ngram Viewer )