corroboration vs refutation

corroboration

noun
  • The act of corroborating, strengthening, or confirming; addition of strength; confirmation 

  • That which corroborates. 

refutation

noun
  • An act of refuting or disproving; the disproving of an argument, opinion, testimony, doctrine or theory by argument or countervailing proof; evidence of falseness. 

  • A vocal answer to an attack on one's assertions. 

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