obscurity vs precedence

obscurity

noun
  • The state of being unknown; a thing that is unknown. 

  • The quality of being difficult to understand; a thing that is difficult to understand. 

  • Darkness; the absence of light. 

precedence

noun
  • Precedent. 

  • The state of preceding in importance or priority. 

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