bas-relief vs high relief

bas-relief

noun
  • A low or mostly-flat sculpture which is carved into a wall, or is in the form of a tile mounted flat to a wall, rather than a fully three-dimensional, free-standing figure. 

adj
  • Refers to any aspect of sculpture which is flat or in the bas relief style. 

high relief

noun
  • A form of classical sculpture in which forms extend from the background by at least half of their depth. 

How often have the words bas-relief and high relief occurred in a corpus of books? (source: Google Ngram Viewer )