clotted cream vs sweet cream

clotted cream

noun
  • A thick, sweet dairy product, made by skimming the thickened layer off the top of unhomogenized cream that has been heated and allowed to stand. Fat content is at least 55%. 

sweet cream

noun
  • Cream: the oily part of milk that rises to the top. 

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