latrine vs small room

latrine

noun
  • Any facility or device used for urination or defecation, whether toilet, lavatory, or outhouse. 

  • An open trench or pit used for urination and defecation. 

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 latrine and small room occurred in a corpus of books? (source: Google Ngram Viewer )