It seems today that every strip mall in America has a mattress store in it. In fact, according to IBISWorld, a market research website, there are at least 9,200 stores selling mattresses in the United States. To put this in perspective, Starbucks has nearly 12,700 domestic locations and people buy more coffee then mattresses.

How did we get here? In part, mattress stores are everywhere because they are incredibly profitable. Unlike most industries where margins can be as low as a few percent, most mattresses are marked up between 40 and 100 percent according to Uptal Dholakia, a professor of marketing at Rice University.

In addition to the high margins, the uptick in mattress stores is indicative of high demand after the Great Recession when many Americans put off buying mattresses.

“People were moving much less; they were staying put in their houses,” said Dholakai in an interview with Freakonomics Radio. “During the recession, for a period of five or six years, people just stopped buying mattresses, and so there was a lot of pent-up demand.”

This demand has in turn led to major consolidation in the mattress industry as Mattress Firm has incorporated Sleepy’s, Mattress Pro, and Sleep Train into itself without closing many retail locations.

So far the demand for mattresses appears to be exceeding the supply as online direct-to-consumer mattress start ups appear. Companies such as Casper, Yogabed, Leesa, and Loom & Leaf, among others, have grown to make up 6 percent of the mattress market. Their early success has prompted investment from venture capitalists who believe that the mattress market will continue to expand to accommodate consumer demand.