penny loafer vs tennis shoe

penny loafer

noun
  • A leather loafer with an ornamental slotted leather band across the top where a coin is often placed. 

tennis shoe

noun
  • A specialty sports shoe designed for playing tennis. 

  • A sneaker (trainer). 

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