happy hour vs rest period

happy hour

noun
  • A time of day, usually in the afternoon or early evening, when a bar or pub offers its drinks at a discounted price. 

  • Any small gathering, usually in the afternoon or early evening, set aside to relax and have a drink. 

  • Flowers. 

rest period

How often have the words happy hour and rest period occurred in a corpus of books? (source: Google Ngram Viewer )