Elysium vs Happy Valley

Elysium

adj
  • of or pertaining to Elysium 

  • blissful; euphoric 

name
  • A region in the northern hemisphere of Mars. 

  • The home of the blessed after death. 

  • A place or state of ideal happiness; paradise. 

Happy Valley

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