irruption vs usurpation

irruption

noun
  • The action of irrupting or breaking into; a violent entry or invasion; an inbreaking; an intrusion. 

  • An abrupt increase in the size of a movement or organization. 

  • An abrupt increase of an animal population. 

usurpation

noun
  • The wrongful seizure of something by force, especially of sovereignty or other authority. 

  • Trespass onto another's property without permission. 

  • A taking or use without right. 

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