eventually vs once upon a time

eventually

adv
  • In the end; at some later time, especially after a long time, a series of problems, struggles, delays or setbacks. 

  • Possibly, potentially, perhaps 

  • For some tail; for all terms beyond some term; with only finitely many exceptions. 

once upon a time

adv
  • A long time ago; at some time in the past (a traditional beginning of children's stories, especially fairy tales). 

How often have the words eventually and once upon a time occurred in a corpus of books? (source: Google Ngram Viewer )