encrust vs graffiti

encrust

verb
  • To inset or affix decorative materials upon (a surface); to inlay into, as a piece of carving or other ornamental object. 

  • To cover with a hard crust. 

  • To form a crust. 

graffiti

verb
  • To mark a surface with such images. 

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

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

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