oligarchy vs tyranthood

oligarchy

noun
  • Those who make up an oligarchic government. 

  • A state ruled by such a government. 

  • A government run by only a few, often the wealthy. 

tyranthood

noun
  • The state or condition of being a tyrant. 

  • A governmental system based on a single ruler wielding absolute authority; tyranny. 

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