dropping vs worn-out

dropping

noun
  • The act of something that drops or falls. 

  • Something dropped; a droplet. 

  • A piece of animal excrement; dung. 

worn-out

adj
  • Damaged due to hard or continued use or exposure until no longer useful or effective. 

  • Exhausted or fatigued from exertion. 

How often have the words dropping and worn-out occurred in a corpus of books? (source: Google Ngram Viewer )