cowboy boot vs tennis shoe

cowboy boot

noun
  • A kind of riding boot, historically worn by cowboys, with a high heel traditionally made of stacked leather, a rounded to pointed toe, a high shaft, and often no lacing. 

tennis shoe

noun
  • A sneaker (trainer). 

  • A specialty sports shoe designed for playing tennis. 

How often have the words cowboy boot and tennis shoe occurred in a corpus of books? (source: Google Ngram Viewer )