hilarity vs laughter

hilarity

noun
  • Something that induces laughter. 

  • A great amount of amusement, usually accompanied by laughter. 

laughter

noun
  • The sound of laughing, produced by air so expelled; any similar sound. 

  • A movement (usually involuntary) of the muscles of the laughing face, particularly of the lips, and of the whole body, with a peculiar expression of the eyes, indicating merriment, satisfaction or derision, and usually attended by a sonorous and interrupted expulsion of air from the lungs. 

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