I did not downvote you, but I see why you were confused. I should have clarified, but one of the links said total grocery sales revenue is $750 billion, so tha

I did not downvote you, but I see why you were confused. I should have clarified, but one of the links said total grocery sales revenue is $750 billion, so that's how I was calculating what fraction of the market Wal-Mart and other stores have. All those tiny grocery stores in dense urban areas account for much smaller slices of the revenue pie.