nest egg vs notecase

nest egg

noun
  • A saving; a reserve of money. 

  • A natural or artificial egg placed in a bird's nest, to encourage the bird to lay its own eggs there. 

  • An egg squash. 

notecase

noun
  • A wallet or billfold (for holding banknotes). 

How often have the words nest egg and notecase occurred in a corpus of books? (source: Google Ngram Viewer )