green bean vs soybean

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. 

soybean

noun
  • The edible seed of this plant. 

  • A legume plant (Glycine max), commonly cultivated for human and animal consumption and as a nitrogen-fixing ground cover. 

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