afternoon tea vs herbal tea

afternoon tea

noun
  • A formal afternoon meal comprising light snacks, accompanied by tea. 

  • A small meal or snack eaten between lunch and dinner (supper); a period of time set aside for this purpose, taken as a break from work or from a conference. 

herbal tea

noun
  • A beverage made by infusing the leaves of various herbs, generally not including true tea (Camellia sinensis). 

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