authorize vs expunge

authorize

verb
  • To grant (someone) the permission or power necessary to do (something); to permit; to sanction or consent to. 

expunge

verb
  • To eliminate completely; to annihilate. 

  • To delete permanently (e-mail etc.) that was previously marked for deletion but still stored. 

  • To erase or strike out. 

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