heaven on earth vs idyll

heaven on earth

idyll

noun
  • A composition, usually instrumental, of a pastoral or sentimental character, e.g. Siegfried Idyll by Richard Wagner. 

  • Any poem or short written piece composed in the style of Theocritus' short pastoral poems, the Idylls. 

  • An episode or series of events or circumstances of pastoral or rural simplicity, fit for an idyll; a carefree or lighthearted experience. 

How often have the words heaven on earth and idyll occurred in a corpus of books? (source: Google Ngram Viewer )