avowal vs testimony

avowal

noun
  • An open declaration of affirmation or admission of knowledge. 

testimony

noun
  • Witness; evidence; proof of some fact. 

  • Statements made by a witness in court. 

  • In a church service (or religious service), a personal account, such as one's conversion, testimony of faith, or life testimony. 

  • An account of first-hand experience. 

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