Hami melon vs muskmelon

Hami melon

noun
  • A variety of muskmelon from Xinjiang, China, particularly associated with Hami City. 

muskmelon

noun
  • A type of melon, Cucumis melo subsp. melo, with sweet orange flesh and a rough skin resembling netting. 

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