cabriolet vs landau

cabriolet

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

  • An automobile with a retractable top. 

landau

noun
  • A type of lightweight, four-wheeled carriage in which the front and back passenger seats face each other. 

  • A style of automobile based around the design of landau carriages. 

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