African-American vs black as Newgate's knocker

African-American

adj
  • Of Black African descent. 

  • Of or pertaining to the culture of African-American people. 

  • An American who is of Sub-Saharan African ancestry. 

  • American and black. 

noun
  • A black American. 

  • Any black person. 

black as Newgate's knocker

adj
  • Completely black in colour. 

How often have the words African-American and black as Newgate's knocker occurred in a corpus of books? (source: Google Ngram Viewer )