Mother Nature vs Nature

Mother Nature

name
  • A personification of nature as woman, stressing fertility and fecundity. Based upon either goddesses of the earth and nature, Gaia, Rhea, or Demeter. 

Nature

name
  • The sum of natural forces reified and considered as a sentient being, will, or principle. 

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