sheltered vs snug as a bug (in a rug)

sheltered

adj
  • Protected, as from wind or weather. 

  • (Of a person) who grew up being overprotected by parents or other guardians; often implies a lack of social skills or worldly experience 

snug as a bug (in a rug)

How often have the words sheltered and snug as a bug (in a rug) occurred in a corpus of books? (source: Google Ngram Viewer )