blackness vs kaffir

blackness

noun
  • The experiences and culture of African-American people. 

  • The state of being of African descent. 

  • The quality of being evil or dismal. 

  • The state or quality of being black in colour. 

kaffir

noun
  • A black person. 

  • South African mining shares 

  • A member of the Nguni people of southern Africa, especially a Xhosa. 

  • A language spoken by the Nguni peoples of southern Africa, especially Xhosa. 

  • In Islamic contexts, a non-Muslim. 

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