inn vs room and board

inn

noun
  • Any establishment where travellers can procure lodging, food, and drink. 

  • A tavern. 

  • One of the colleges (societies or buildings) in London, for students of the law barristers. 

room and board

noun
  • A place of lodging with daily meals, usually provided in return for rent or other considerations. 

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