pierce vs scarification

pierce

noun
  • A pierced earring. 

verb
  • To penetrate; to affect deeply. 

  • To get to the heart or crux of (a matter). 

  • To create a hole in the skin for the purpose of inserting jewelry. 

  • to break or interrupt abruptly 

  • To puncture; to break through. 

scarification

noun
  • A medieval form of penance in which the skin was damaged with a knife or hot iron. 

  • The act of scarifying: raking the ground harshly to remove weeds, etc. 

  • A route of administration for some vaccinations and tests: rather than hypodermic injection, the site is inoculated intradermally not with any injection but rather only with small, shallow pricks or scratches; the needle is not hollow. 

  • The scratching, etching, burning / branding, or superficially cutting designs, pictures, or words into the skin as a permanent body modification. 

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