Sir vs seignior

Sir

noun
  • The titular prefix given to a knight or baronet. 

seignior

noun
  • A feudal lord; a nobleman who held his lands by feudal grant; any lord (holder) of a manor 

  • A title of respect, formerly corresponding (especially in France) approximately to Sir. 

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