commoner vs khan

commoner

noun
  • A member of the common people who holds no title or rank. 

  • Someone who has a right over another's land. They hold common rights because of residence or land ownership in a particular manor, especially rights on common land. eg: centuries-old grazing rights 

  • Someone who is not of noble rank. 

khan

noun
  • A noble or man of rank in various Muslim countries of Central Asia, including Afghanistan. 

  • A ruler over various Turkish, Tatar and Mongol peoples in the Middle Ages. 

  • A caravanserai; a resting-place for a travelling caravan. 

  • An Ottoman sultan. 

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