expound vs summarize

expound

verb
  • To make a statement, especially at length. 

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

summarize

verb
  • To prepare a summary of (something). 

  • To give a recapitulation of the salient facts; to recapitulate or review. 

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