Sambo vs kaffir

Sambo

noun
  • A black person, especially one who is accommodating or servile towards whites; an Uncle Tom. 

name
  • A nickname from the given name Samantha. 

  • A Russian martial art and combat sport. 

  • A nickname from the given name Samuel. 

kaffir

noun
  • 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. 

  • A black person. 

  • In Islamic contexts, a non-Muslim. 

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