area of authority vs bailiwick

area of authority

noun
  • the extent of someone's expertise, authority, activity or knowledge 

bailiwick

noun
  • A person's concern or sphere of operations, their area of skill or authority. 

  • The district within which a bailie or bailiff has jurisdiction. 

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