Inner vs seven seas

Inner

noun
  • An inhabitant of the inner planets of the Solar System 

seven seas

noun
  • All of the oceans of the world. (In a common modern interpretation, the seven seas are the North and South Atlantic, North and South Pacific, Indian, Arctic and Antarctic, but historical interpretations differ widely; see the Wikipedia article for this.) 

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