Augustinian vs Gray Friar

Augustinian

adj
  • of, or relating to St Augustine of Hippo 

  • of, or relating to several religious orders influenced by him 

noun
  • A follower of St Augustine or his doctrines, especially on predestination and irresistible grace. 

  • A friar or monk of any Augustinian order. 

Gray Friar

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