Demeter vs Mother Earth

Demeter

name
  • The goddess of the fertility of the Earth and harvests, protector of marriage and social order; daughter of Cronos and Rhea, mother to Persephone. 

  • 1108 Demeter, a main belt asteroid. 

Mother Earth

name
  • The goddess of the earth in various cultures. 

  • The personification of the Earth, (chiefly) conceived as a fertile, nurturing, and loving mother. 

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