expound vs narrate

expound

verb
  • To set out the meaning of; to explain or discuss at length 

  • To make a statement, especially at length. 

narrate

verb
  • To relate (a story or series of events) in speech or writing. 

  • To give an account. 

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