green bean vs yardlong bean

green bean

noun
  • The immature pods of any kind of bean plant, eaten as a vegetable. 

  • The immature pods of numerous varieties of the common bean, Phaseolus vulgaris. 

yardlong bean

noun
  • A vigorous climbing annual vine (Vigna unguiculata subsp. sesquipedalis) grown primarily for its strikingly long (35-75 cm) immature pods with uses very similar to that of a green bean. 

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