HORSE vs hockey stick

HORSE

noun
  • A poker variant consisting of five different poker variants, with the rules changing from one variant to the next after every hand. 

hockey stick

noun
  • A stick used to handle the puck in ice hockey, having a flat, angled blade at the end. 

  • A stick used to handle the ball in field hockey, having a flat-faced hook at the end. 

  • A statistical trend in a graph of survey data in which most of the results are flat and then the graph suddenly peaks in a steep near-vertical direction. 

  • A playing card with the rank of seven. 

How often have the words HORSE and hockey stick occurred in a corpus of books? (source: Google Ngram Viewer )