berlin vs landau

berlin

noun
  • A four-wheeled carriage with a separate sheltered seat behind the body. 

  • Coordinate terms: calèche, landau 

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 berlin and landau occurred in a corpus of books? (source: Google Ngram Viewer )