sadness vs suffering

sadness

noun
  • The state or emotion of being sad. 

  • An event in one's life that causes sadness. 

suffering

noun
  • The condition of someone who suffers; a state of pain or distress. 

adj
  • Experiencing pain; characterized by suffering. 

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