cush-cush vs yampee

cush-cush

noun
  • A tropical American yam with small yellow-skinned edible tubers: Dioscorea trifida 

  • Synonym of couche-couche 

yampee

noun
  • A variety of yam, Dioscorea trifida, smaller than a regular yam. 

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