(FORTUNE Magazine) – Pottery Barn and Petco. Starbucks and Staples. Tommy and Target. Never mind Wal-Mart. Do you ever get the feeling that there are more stores out there than ever? If England is the nation of shopkeepers, we must be the nation of shopbuilders! How else to explain the insane proliferation of retailing in this country?

Are there data to back this up? Oh, yes there are, sadly enough. Street Life usually doesn't concern itself with concepts that sound suspicious, like "gross leaseable area," known by retailing egg-heads as GLA (or, even better, GLA per capita), but some figures I got hold of recently just blow my mind. The numbers, by the way, come from the National Research Bureau's Shopping Center Census, which is an estimate of the total population of shopping centers in the U. S. They say it's the "most authoritative sample of data available on retail properties" out there, and who am I to argue? (Don't answer that!) Here you go: In 1986 there were 28,496 shopping centers in the U.S., boasting 3.5 billion square feet of space. Today there are 46,438 malls and such with 5.8 billion square feet of space.

Ah, you say, but the country has grown during those 17 years. Yes, it has. For the record, the U.S. population was 238 million back in 1986, and it's currently 286 million. But guess what? The number of malls is growing faster than the number of babies. Here's where that GLA per capita figure comes in. In 1986 GLA per capita in America was 14.7 square feet. Today the figure is 20.2 square feet. Basically that means that retailing square footage per American has increased more than 37% since 1987. So there you have the unassailable evidence. There are indeed more--and bigger--stores than ever in this country, even after adjusting for population growth.

As far as buying the stuff that's in all those stores, well, yes, it's true that Americans have more wealth than they did in the 1980s. But guess what else? We're up to our eyeballs in debt paying for the junk we've been buying. American households owe on average $8,940 on their credit cards, up 173% from 1992, when we had an average outstanding balance of $3,275.

This is all part of a disturbing overleveraging and overcapacity problem we have in this country. For the past 20 years the mantra from Wall Street has been that if an asset isn't leveraged, it's underutilized. In other words, if you can borrow against something--a factory, a business, a cash flow--why, by golly, you should. But what if you don't need the capital? Heck, son, you always need capital! Use it to expand! Create new sports teams, build new cookie factories, develop new shopping malls. And so what do we end up with? We have the Tampa Bay Devil Rays, and bags and bags of Keebler cookies, and 22 shopping malls around Columbus. (And as we've seen, there is a parallel overleveraging and overcapacity process on the consumer side with credit cards and credit card debt.) Meanwhile the S&P 500 Retailing index is up 215% over the past ten years, way ahead of the broader index's 121% rise.

Now, I'm not a doom-and-gloomer, but trends like this always unwind one way or the other. Where we stand now is that when a store closes or goes bankrupt, credit is easy enough to get that another retailer is always there to move in. A higher interest rate environment would be likely to change that. Let's hope it doesn't get too ugly.