anecdote vs shaggy-dog story

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). 

shaggy-dog story

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