niggergirl vs tar baby

niggergirl

noun
  • A young black woman. 

tar baby

noun
  • A black person. 

  • A difficult, abstract problem that worsens as one attempts to handle it; a "sticky" situation, especially one where attempts to make it better only make it worse. 

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