bedpan vs john

bedpan

noun
  • A pan used for urination and defecation while in bed, now usually for reasons of medical necessity or convenience. 

john

noun
  • A device or place to urinate and defecate: now usually a toilet or lavatory, but also (dated) a chamber pot or outhouse. 

  • A male mule. 

  • A Western man traveling in East Asia. 

  • A prostitute's client. 

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