cave painting vs graffiti

cave painting

noun
  • The paintings resulting from this activity regarded collectively, especially if prehistoric; cave art; (countable) an individual painting of this type. 

  • The activity of applying pigments to the interior surfaces of caves to create images, especially when carried out in prehistoric times. 

graffiti

noun
  • Informal inscriptions, figure drawings, etc., as opposed to official inscriptions. 

  • Drawings or words drawn on a surface in a public place, usually made without authorization. 

verb
  • To mark a surface with such images. 

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