(FORTUNE Magazine) – It seems there are more people selling the blues these days than singing them. According to the Memphis-based Blues Foundation, the number of U.S. blues clubs has grown 52% since 1990, to 1,360. The number of blues record labels has gone up 26% to 250 nationwide. Driving the trend: Audiences dispirited by their own hard times and the weak economy prefer the gritty realism of blues over much of the current syrupy popular music. According to David Less, director of the Blues Foundation, blues always flourish when popular music gets slick -- like during the early 1950s, heyday of Doris Day, and the disco-driven late 1970s. Says he: ''People today like the vitality and raw edge the blues bring. You listen to contemporary hit radio, and there's a lot of sameness to it.'' Legendary bluesmen like B.B. King are capitalizing on the trend. King and his partners are opening a Los Angeles branch of B.B. King's, their Memphis club, and are planning to expand into San Francisco and New York City as well. And bigtime businessmen are starting to get in on the act. Isaac Tigrett, who % put Hard Rock Cafes everywhere from Cancun to Reykjavik, has opened the first in a series of blues club/restaurants. His investors include Sir James Goldsmith, Harvard University, and actors River Phoenix and Dan Aykroyd. The first House of Blues, as the venture is called, opened in Cambridge, Massachusetts, last November. Others are due in Los Angeles, New Orleans, and New York within a year. And who knows, maybe even Reykjavik.