mitigatory vs narcotic

mitigatory

adj
  • reducing, lessening the effects of something, generally something painful or uncomfortable 

narcotic

adj
  • Of, or relating to narcotics. 

  • Inducing sleep; causing narcosis. 

noun
  • Any substance or drug that reduces pain, induces sleep and may alter mood or behaviour; in some contexts, especially in reference to the opiates-and-opioids class, especially in reference to illegal drugs, and often both. 

  • Any type of numbing or soothing drug. 

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