mournful vs threnodial

mournful

adj
  • Filled with grief or sadness; being in a state in which one mourns. 

  • Fit to inspire mourning; tragic. 

threnodial

adj
  • Pertaining or similar to a threnody. 

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