demonstrably vs incontrovertibly

demonstrably

adv
  • In such a manner that is capable of being demonstrated, shown, or proved. 

incontrovertibly

adv
  • In an incontrovertible manner; in a manner not capable of being denied, challenged, or disputed. 

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