restroom vs teahouse

restroom

noun
  • A room containing a public toilet: a public lavatory. 

teahouse

noun
  • a public lavatory, particularly (dated US gay slang) as a meeting place for gay men. 

  • A cafe or restaurant that serves tea, usually with light food. 

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