autocracy vs decemvirate

autocracy

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

  • An instance of this government. 

decemvirate

noun
  • A group of ten people, especially (politics) a council of ten men sharing office or power and particularly (historical) the groups of ten men who reformed and codified Roman law circa 450 BCE. 

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