certifiably vs needless to say

certifiably

adv
  • Undoubtedly, demonstrably. 

  • With the potential for certification. 

  • To a great extent. 

  • Genuinely 

needless to say

adv
  • Clearly, obviously. 

How often have the words certifiably and needless to say occurred in a corpus of books? (source: Google Ngram Viewer )