bathtub vs car wash

bathtub

noun
  • A large container for holding water in which a person may bathe (take a bath). 

car wash

noun
  • An instance of washing a car, especially such a place. 

  • An event at which people (often students) wash cars, often for a small fee or donation 

  • A place at which a car is washed, usually for a fee and often mechanically by driving the car through a tunnel. 

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