expiration date vs expiry

expiration date

noun
  • A date by which an object either should not be used or loses its value, depending upon the item. 

expiry

noun
  • Synonym of expiration date 

  • End; termination; expiration. 

  • Death. 

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