dressing room vs gentlemen's room

dressing room

noun
  • A room used for dressing or changing clothes. 

  • A room in a theatre or other performance venue in which performers may change costumes and apply makeup. 

  • A changing room at a recreational or sports venue. 

  • A small room adjoining a domestic bedroom where people may dress or undress in privacy. 

gentlemen's room

noun
  • Any room intended for use by men 

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

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