fairground vs theme park

fairground

noun
  • A commercially-operated collection of rides, games and other entertainment attractions; an amusement park. 

  • An area where a fair (an event for public entertainment) or other public event is held; a showground. 

theme park

noun
  • An amusement park that has one or more specific central themes, often as part of its name 

How often have the words fairground and theme park occurred in a corpus of books? (source: Google Ngram Viewer )