due date vs usance

due date

noun
  • The date of payment in financial arrangements. 

  • The date on which a pregnant woman is expected to give birth. 

  • The date by which a book (or other item) borrowed from a library must be returned. 

  • The date by which a task is supposed to be completed. 

usance

noun
  • The length of time permitted for the payment of a bill of exchange. 

  • Customary or habitual usage. 

  • Use. 

  • The interest paid on a borrowed sum, usury. 

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