gentlemen's room vs small room

gentlemen's room

noun
  • A waiting room in a railway station or other public building, often including a separate lavatory. 

  • Any room intended for use by men 

small room

noun
  • A lavatory: a room intended for urination and defecation. 

  • Used other than figuratively or idiomatically: see small, room. 

How often have the words gentlemen's room and small room occurred in a corpus of books? (source: Google Ngram Viewer )