millionaire vs plutocrat

millionaire

noun
  • A person whose net worth is at or greater than one million units of the local currency; a multimillionaire. 

  • A person whose net worth is at or greater than one million units of the local currency, but less than two million. 

plutocrat

noun
  • Someone who rules by virtue of his or her wealth. 

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