light at the end of the tunnel vs pessimism

light at the end of the tunnel

noun
  • A vision of a bright light, surrounded by darkness, seen by a dying person 

  • A better situation after long hardship. 

pessimism

noun
  • A general belief that bad things will happen. 

  • The condition of being pessimal. 

  • The doctrine that this world is the worst of all possible worlds. 

How often have the words light at the end of the tunnel and pessimism occurred in a corpus of books? (source: Google Ngram Viewer )