Sambo vs shitskin

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. 

shitskin

noun

  • A person with dark-coloured skin. 

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