corroboree vs war dance

corroboree

noun
  • A nocturnal dance held by Australian Aborigines, for social, celebratory or warlike purposes. 

  • A song or chant made for such a festivity. 

  • Any noisy, late-night gathering or disturbance. 

war dance

noun
  • A ceremonial dance performed before a major battle or after a victory, usually by a tribe. 

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