elector vs tsar

elector

noun
  • A person eligible to vote in an election; a member of an electorate, a voter. 

  • A member of an electoral college; specifically (US) an official selected by a state as a member of the Electoral College to elect the president and vice president of the United States. 

  • A person eligible to vote to elect a Member of Parliament. 

tsar

noun
  • A person with great power; an autocrat. 

  • An emperor of Russia (1547 to 1917) and of some South Slavic states. 

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