archdiocese vs archiepiscopacy

archdiocese

noun
  • An area administered by an archbishop; the ecclesiastical hierarchy of this area, also under the archbishop. 

archiepiscopacy

noun
  • The position or dignity of an archbishop. 

  • The form of episcopacy in which the chief power is in the hands of archbishops. 

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