This product image provided by Levi Strauss shows the company’s Knit Jeans, made of stretch cotton knit that look like jeans but feel like sweatpants. Companies, including Levi Strauss, which invented the first pair of blue jeans 141 years ago, acknowledge that the jeans business has been hurt by what the fashion industry dubs the “athleisure” trend. That has led them to create new versions of classic denim that are more “stretchy” and mimic the comfort of sweatpants. (AP Photo/Levi Strauss)

NEW YORK — Americans’ obsession with jeans is beginning to wear thin.

Jeans long have been a go-to staple in closets across the country. After all, not many pieces of clothing are so comfortable they can be worn daily, yet versatile enough to be dressed up or down.

But sales of the iconic blues fell 6 percent during the past year after decades of almost steady growth. Why? People more often are sporting yoga pants and leggings instead of traditional denim.

The shift is partly due to a lack of new designs since brightly colored skinny jeans were a hit a couple years back. It’s also a reflection of changing views about what’s appropriate attire for work, school and other places that used to call for more formal attire.

“Yoga pants have replaced jeans in my wardrobe,” said Anita Ramaswamy, a Scottsdale, Arizona high-school senior who is buying more leggings and yoga pants than jeans. “You can make it as sexy as skinny jeans, and it’s more comfortable.”

To be sure, the jeans business isn’t dead: Customer Growth Partners, a retail consultancy, estimates denim accounts for 20 percent of annual sales at the nation’s department stores.

But sales of jeans in the U.S. fell 6 percent to $16 billion during the year that ended in June, according to market research firm NPD Group, while sales of yoga pants and other “active wear” climbed 7 percent to $33.6 billion.

And 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.