dropping vs quelling

dropping

noun
  • The act of something that drops or falls. 

  • Something dropped; a droplet. 

  • A piece of animal excrement; dung. 

quelling

noun
  • The act by which something is quelled. 

adj
  • causing something to quell or be quelled 

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