nest egg index
n.— «This “nest egg index,” as it was called, was conducted by A.G. Edwards, a St. Louis-based financial services company. It looked at money-saving data from 318 cities.» —“West Side or East: The battle of the savers” by Alan Julian Evansville Business Journal (Illinois) Dec. 18, 2005. (source: Double-Tongued Dictionary)
Further reading
What kind of book do people ask for most often in prison? Romance novels? No. The Bible? No. The most requested books by far are … dictionaries! A number of volunteer organizations gather and distribute used dictionaries to help inmates with...
What if, instead of being an inanimate object, a dictionary were alive? That’s the idea behind a lavishly illustrated new children’s book called The Dictionary Story (Bookshop|Amazon) by Oliver Jeffers and Sam Winston. This is part of a...