baseball vs rugby union

baseball

noun
  • A sport common in North America, the Caribbean, and Japan, in which the object is to strike a ball so that one of a nine-person team can run counter-clockwise among four bases, resulting in the scoring of a run. The team with the most runs after termination of play, usually nine innings, wins. 

  • The ball used to play the sport of baseball. 

  • A variant of poker in which cards with baseball-related values have special significance. 

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 baseball and rugby union occurred in a corpus of books? (source: Google Ngram Viewer )