Shangri-La vs land of Nod

Shangri-La

noun
  • A place of complete bliss, delight, and peace, especially one seen as an escape from ordinary life; a paradise. 

land of Nod

name
  • The state of sleep, or an imaginary place that one inhabits when asleep. 

How often have the words Shangri-La and land of Nod occurred in a corpus of books? (source: Google Ngram Viewer )