irrefutable vs unequivocal

irrefutable

adj
  • undeniable; unable to be disproved or refuted 

unequivocal

adj
  • Unambiguous; without equivocation or ambiguity; singularly clear, unmistakable, or unquestionable 

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