favela vs rookery

favela

noun
  • A slum or shantytown, especially in Brazil 

rookery

noun
  • A place where criminals congregate, often an area of a town or city. 

  • A colony of breeding birds or other animals. 

  • A crowded tenement. 

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