deferment vs downtime

deferment

noun
  • An act or instance of deferring or putting off. 

  • Officially sanctioned postponement of compulsory military service. 

downtime

noun
  • The amount of time lost due to forces beyond one's control, as with a computer crash. 

  • A period of time set aside for rest and relaxation; leisure time. 

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