faithfully vs yours faithfully

faithfully

adv
  • In a faithful manner. 

  • A conventional formula for ending a letter, used when the salutation addresses the person for whom the letter is intended using an honorific. 

yours faithfully

adj
  • A polite, formulaic end to a letter, used especially when the sender does not know the recipient's name, for example in a business letter. 

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