affidavit vs averment

affidavit

noun
  • A signed document wherein an affiant makes a sworn statement. 

averment

noun
  • A positive statement of facts; an allegation; an offer to justify or prove what is alleged. 

  • The act of averring, or that which is averred; positive assertion. 

  • verification; establishment by evidence. 

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