anecdote vs backstory

anecdote

noun
  • A previously untold secret account of an incident. 

  • An account which supports an argument, but which is not supported by scientific or statistical analysis. 

  • A short account of a real incident or person, often humorous or interesting. 

verb
  • To tell anecdotes (about). 

backstory

noun
  • A fictitious account of a person's history designed to conceal their actual history and motives. 

  • The previous life and experiences of a person, especially a character in a dramatic work, but also a real-life person. 

  • A prequel. 

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