cabriolet vs hardtop

cabriolet

noun
  • An automobile with a retractable top. 

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

hardtop

noun
  • The removable rigid roof of a convertible or sports car. 

  • An indoor cinema with a roof, as opposed to a drive-in. 

  • A car with such a roof. 

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