happily vs thankfully

happily

adv
  • By good chance; fortunately, successfully. 

  • With good will; in all happiness; willingly. 

  • In a happy or cheerful manner; with happiness. 

thankfully

adv
  • fortunately, gratefully. 

  • In a thankful manner; giving thanks. 

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