gladness vs optimism

gladness

noun
  • The state of being glad; joy. 

optimism

noun
  • a tendency to expect the best, or at least, a favourable outcome 

  • the doctrine that this world is the best of all possible worlds 

  • the belief that good will eventually triumph over evil 

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