affirmation vs attestation

affirmation

noun
  • That which is affirmed; a declaration that something is true. 

  • A form of self-forced meditation or repetition; autosuggestion. 

  • The solemn declaration made by Quakers and others incapable of taking an oath. 

attestation

noun
  • A thing that serves to bear witness, confirm, or authenticate; validation, verification, documentation. 

  • The process, performed by accountants or auditors, of providing independent opinion on published financial and other business information of a business, public agency, or other organization. 

  • A confirmation or authentication. 

  • An appearance in print or otherwise recorded on a permanent medium. 

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