men's room vs operating theatre

men's room

noun
  • Other rooms intended for use by men, as waiting rooms, dressing rooms, locker rooms, etc. 

  • A lavatory intended for use by men, often including urinals in addition to toilets. 

operating theatre

noun
  • A room in a hospital used for performing surgery (originally designed for operations in front of observers). 

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