euthanatize vs fall asleep

euthanatize

verb
  • To euthanize. 

fall asleep

verb
  • To die (often seen on gravestones). 

  • To be affected by paresthesia; to go numb. 

  • To pass from a state of wakefulness into sleep. 

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