neger vs nigga

neger

noun
  • Synonym of nigger 

nigga

noun
  • A black person (usually male), especially an African American. 

  • A male as opposed to a female. 

  • A close and loyal friend. 

  • Any person, though chiefly male. 

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