authorization vs permissibility

authorization

noun
  • An act of authorizing. 

  • (A document giving) formal sanction, permission or warrant. 

  • Permission. 

  • Permission, possibly limited, to spend funds for a specific budgetary purpose. 

permissibility

noun
  • A permissible act. 

  • The condition of being permissible; legitimacy; allowability. 

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