Weltschmerz vs pessimism

Weltschmerz

noun
  • An apathetic or pessimistic view of life; depression concerning or discomfort with the human condition or state of the world; mal du siècle, world-weariness. 

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 Weltschmerz and pessimism occurred in a corpus of books? (source: Google Ngram Viewer )