cabriolet vs roadster

cabriolet

noun
  • An automobile with a retractable top. 

  • A light two- or four-wheeled carriage with a folding top, pulled by a single horse. 

roadster

noun
  • An open automobile having a front seat and a rumble seat. 

  • A person who lives along the road. 

  • a sea-going vessel riding at anchor in a road or bay. 

  • A clumsy vessel that works its way from one anchorage to another by means of the tides. 

  • A bicycle, or tricycle, adapted for common roads, rather than for the racing track, usually of classic style and steel-framed construction. 

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