That's a really interesting idea. A potential problem is finding a similar, standardized source of food price data (if you want to include that). Some data are

That's a really interesting idea. A potential problem is finding a similar, standardized source of food price data (if you want to include that). Some data are published by the USDA ERS [1], but it's far from comprehensive. [1] e.g. http://www.ers.usda.gov/data-products/quarterly-food-at-home-price-database.aspx http://www.ers.usda.gov/data-products/quarterly-food-at-home...