footy vs international rules football

footy

noun
  • The game or sport of football, usually Australian rules football or rugby league, but not soccer 

  • A football fan. 

  • Football (association football) (soccer in US, Canada, Australia, New Zealand) 

  • The ball used in a game of footy. 

  • A short sock. 

international rules football

noun
  • A sport created as a mixture of Australian rules football and Gaelic football, to allow international matches between Australia and Ireland. 

How often have the words footy and international rules football occurred in a corpus of books? (source: Google Ngram Viewer )