agave vs maguey

agave

noun
  • A plant of the genus Agave, which includes the maguey or century plant (Agave americana), which produces a gigantic flower stem at maturity. 

maguey

noun
  • Any of various large agaves of Mexico and the southern US, especially the American aloe, Agave americana. 

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