brant vs declivitous

brant

adj
  • steep, precipitous. 

  • smooth; unwrinkled 

noun
  • Any of several wild geese, of the genus Branta, that breed in the Arctic, but especially the brent goose, Branta bernicla. 

declivitous

adj
  • Descending gradually; moderately steep; sloping; downhill. 

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