bilberry vs foxberry

bilberry

noun
  • The shrub of the above-mentioned plant. 

  • Vaccinium myrtillus, the wild European blueberry of the cowberry family. 

foxberry

noun
  • The berry of this plant. 

  • The plant cowberry or lingonberry, Vaccinium vitis-idaea. 

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