nirvana vs rainbows and unicorns

nirvana

noun
  • State of paradise; heightened or great pleasure. 

  • Complete cessation of suffering; a blissful state attained through realization of sunyata; enlightened experience. 

rainbows and unicorns

noun
  • A wonderful (but often unrealistic) scenario. 

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