Everything must go at the soon to be closing Sears store in the New York borough of the Bronx.

Stores still matter.

They give shoppers a place to try on merchandise, return unwanted items and pick up things they need that minute. Yet as more buying occurs online, retailers need to react. Often, that means closing stores.

Since January 2014, mall traffic has declined every month except for one, according to a new report by Cowen & Company analyst Oliver Chen. While the internet has played a role in that steady erosion, so has a surplus of retail real estate.

The number of U.S. malls has roughly quadrupled to 1,220 since 1970. Meanwhile, the country’s population has grown by less than half that amount…