You've misread my comment. The cocktail shrimp example is why "nuh uh, my personal number is higher" is not a valuable data point. Maybe you go to an expensive store, maybe you buy the fancier lettuce, maybe your basket includes some things you consider staples that aren't all that common nationally.

It's why we have a nation-wide check on the prices of a well-researched selection of staples in the average proportions they make up in an average person's budget, rather than polling random people on the Internet for anecdotes. That number is far more useful.