capability vs efficiency

capability

noun
  • the power or ability to generate an outcome 

  • A digital token allowing a user or process to interact in a specified way with an object that is subject to access control. 

efficiency

noun
  • The extent to which a resource is used for the intended purpose; the ratio of useful work to energy expended. 

  • A one-room apartment. 

  • The extent to which time is well used for the intended task. 

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