sugar cane vs sugar-cane

sugar cane

noun
  • A tropical grass of the genus Saccharum (especially the species Saccharum officinarum, including hybrids) having stout, fibrous, jointed stalks, the sap of which is a source of sugar. 

  • A candy cane, an edible candy in the shape of a cane. 

sugar-cane

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