concurrency vs expediency

concurrency

noun
  • The property or an instance of being concurrent; something that happens at the same time as something else. 

  • A property of systems where several processes execute at the same time. 

  • A stretch of road that is shared between two or more numbered or named routes. 

expediency

noun
  • An expedient. 

  • The quality of being fit or suitable to effect some desired end or the purpose intended; suitability for particular circumstance or situation. 

  • Pursuit of the course of action that brings the desired effect even if it is unjust or unprincipled. 

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