Jerusalem artichoke vs girasol

Jerusalem artichoke

noun
  • The tuber of this plant, eaten as a vegetable. 

  • A variety of sunflower, Helianthus tuberosus, native to North America, having yellow flower heads and edible tubers. 

girasol

noun
  • A fire opal. 

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