compulsory purchase vs superiority

compulsory purchase

noun
  • The power of a state to expropriate private land within its jurisdiction for public use. 

superiority

noun
  • The right which the superior enjoys in the land held by the vassal. 

  • The state of being superior. 

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