afterword vs peroration

afterword

noun
  • an epilogue. 

  • an appendix. 

  • a postscript. 

peroration

noun
  • The concluding section of a discourse, either written or oral, in which the orator or writer sums up and commends his topic to his audience, particularly as used in the technical sense of a component of ancient Roman oratorical delivery. 

  • A discourse or rhetorical argument in general. 

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