red pepper vs sweet pepper

red pepper

noun
  • A red-colored, ripe, bell or sweet pepper. Unripe peppers of this variety are green and edible but not as sweet. 

  • Spicy pepper. 

sweet pepper

noun
  • The fruit of a non-spicy cultivar of pepper, Capsicum annuum, marketed in green-, red-, yellow- and orange-skinned varieties. 

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