adversity vs freak accident

adversity

noun
  • An event that is adverse; calamity. 

  • The state of adverse conditions; state of misfortune or calamity. 

freak accident

noun
  • An incident, especially one that is harmful, occurring under highly unusual and unlikely circumstances. 

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