cranium vs upper story

cranium

noun
  • Synonym of skull. 

  • That part of the skull consisting of the bones enclosing the brain, but not including the bones of the face or jaw. 

  • The upper portion of the skull, including the neurocranium and facial bones, but not including the jawbone (mandible). 

upper story

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