Published: Sep 05, 2014 10:56 AM EDT

NEW YORK, N.Y.- Americans' obsession with jeans is beginning to fade.
    
Sales are falling as the market share of clothing such as yoga pants and leggings grow. The research firm NPD Group says sales of jeans in the U.S. dropped 6 percent during the past year after decades of fairly steady growth.
    
Meanwhile, sales of "active wear" like yoga pants climbed 7 percent, more than doubling the $16 billion people spent on jeans. But retail consultant Customer Growth Partners estimates denim still accounts for 20 percent of annual sales at the nation's department stores.
    
Levi Strauss, which invented the first pair of blue jeans 141 years ago, is among jean makers that acknowledge their business has been hurt by what the fashion industry dubs the "athleisure" trend. That's led them to create new versions of classic denim that are more "stretchy" and mimic the comfort of sweatpants.

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