nerd vs sad case

nerd

noun
  • A member of a subculture revolving around intellectualism, video games, fantasy and science fiction, comic books and assorted media. 

  • One who has an intense, obsessive interest in something. 

  • A person who is intellectual but generally introverted. 

sad case

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