lame duck vs sad sack

lame duck

noun
  • A person or thing that is helpless, inefficient, or disabled. 

  • An elected official who has lost the recent election or is not eligible for reelection and is marking time until leaving office. 

sad sack

noun
  • An incompetent or inept person. 

  • A perennial failure or victim of misfortune. 

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