feedstock vs raw material

feedstock

noun
  • Any bulk raw material constituting the principal input for an industrial process. 

raw material

noun
  • Any physical product serving as input to a factory or other installation which processes it. 

  • A material in its unprocessed, natural state considered usable for manufacture. 

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