certainty vs matter of course

certainty

noun
  • An instance of being certain. 

  • The state of being certain. 

  • A fact or truth unquestionably established. 

matter of course

noun
  • An expected or customary outcome. 

  • A natural or logical outcome. 

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