backstair vs chest of drawers

backstair

noun
  • The backstairs (stairs at the rear of a building). 

adj
  • clandestine, secret or furtive 

chest of drawers

noun
  • A piece of furniture which has multiple parallel, horizontal drawers stacked one above each other, used mainly for the storage of clean clothes. 

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