obtund vs take the edge off

obtund

verb
  • To reduce the edge or effects of; to mitigate; to dull. 

take the edge off

verb
  • To diminish the effects of (something unpleasant or severe); to dull. 

  • To relax or unwind (by consuming alcohol or other psychoactive substances). 

How often have the words obtund and take the edge off occurred in a corpus of books? (source: Google Ngram Viewer )