protestation vs retraction

protestation

noun
  • A declaration in common-law pleading, by which the party interposes an oblique allegation or denial of some fact, protesting that it does or does not exist, and at the same time avoiding a direct affirmation or denial. 

  • a formal solemn objection or other declaration 

retraction

noun
  • A statement printed or broadcast in a public forum which effects the withdrawal of an earlier assertion, and which concedes that the earlier assertion was in error. 

  • A continuous function from a topological space onto a subspace which is the identity on that subspace. 

  • An act or instance of retracting. 

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