fructose vs glycogen

fructose

noun
  • A monosaccharide ketose sugar, formula C₆H₁₂O₆. 

glycogen

noun
  • A polysaccharide that is the main form of carbohydrate storage in animals; converted to glucose as needed. 

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