Mother of Mercy vs Virgin Mary

Mother of Mercy

name

  • The Virgin Mary, the mother of Christ. 

Virgin Mary

name

  • Mary, the mother of Christ. 

noun

  • A drink made with tomato juice and spices, resembling a Bloody Mary, but without alcohol. 

How often have the words Mother of Mercy and Virgin Mary occurred in a corpus of books? (source: Google Ngram Viewer )