penny loafer vs sneaker

penny loafer

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

sneaker

noun
  • A sneaker male. 

  • An athletic shoe with a soft, rubber sole. A trainer. 

  • One who sneaks. 

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