adversity vs fortuity

adversity

noun
  • An event that is adverse; calamity. 

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

fortuity

noun
  • A fortuitous event; an accident. 

  • The state of being fortuitous. 

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