international football vs rugby union

international football

noun
  • Soccer. 

  • Used other than figuratively or idiomatically: see international, football. 

  • The combination of Canadian football and American football. 

rugby union

noun
  • A form of rugby football, historically amateur, having 15 players per side; points are scored for a try, penalty, drop kick or conversion. 

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