curricle vs passenger car

curricle

noun
  • A light two-wheeled carriage large enough for the driver and a passenger and drawn by a carefully-matched pair. 

passenger car

noun
  • A motor vehicle designed to carry (a few) passengers; a motorcar. 

  • A railroad car designed to carry passengers. 

How often have the words curricle and passenger car occurred in a corpus of books? (source: Google Ngram Viewer )