deferral vs prepayment

deferral

noun
  • A prepayment. 

  • An accrual. 

  • An act of deferring, a deferment. 

prepayment

noun
  • A payment in advance. 

  • An asset recognized in respect an expense incurred in a period for which the benefit will be received in a future period. 

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