centumvirate vs quinquevirate

centumvirate

noun
  • A group of one hundred people, especially (politics) a council of about 100 men who share power or rule, particularly (historical) such a group in ancient Rome. 

quinquevirate

noun
  • An official group of five people, especially a council of five men sharing office or rule. 

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