slum vs slum area

slum

noun
  • A dilapidated neighborhood where many people live in a state of poverty. 

  • Slumgullion; a meat-based stew. 

  • Inexpensive trinkets awarded as prizes in a carnival game. 

verb
  • To visit a neighborhood of a status below one's own. 

slum area

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