cooler vs thank-you note

cooler

noun
  • A bouncer or doorman. 

  • A cold deck. 

  • An insulated bin or box used with ice or freezer packs to keep food or beverages cold while picnicking or camping. 

  • Anything which cools. 

  • A device for refrigerating dead bodies in a morgue. 

  • A type of drink made with alcohol, especially wine, mixed with fruit juice. 

  • A prison. 

  • samalamig 

thank-you note

How often have the words cooler and thank-you note occurred in a corpus of books? (source: Google Ngram Viewer )