I know vs eureka

I know

phrase
  • An emphatic assertion that one has a solution, an answer, or an idea. 

  • A response used to indicate that speaker was in agreement with the preceding statement before it was made. 

eureka

intj
  • An exclamation indicating sudden discovery. 

noun
  • Synonym of constantan (“copper-nickel alloy”) 

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