autocracy vs novemvirate

autocracy

noun
  • An instance of this government. 

  • A form of government in which unlimited power is held by a single individual. 

novemvirate

noun
  • A group of nine people, especially (politics) a council of nine men who share office or rule. 

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