discoloration vs fingermark

discoloration

noun
  • A discolored spot; a stain. 

  • The act of discoloring, or the state of being discolored; alteration of hue or appearance. 

fingermark

noun
  • A blemish made by a dirty finger. 

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