Market research company discovered that jeans introduced in 2016 generated the most dollar gains for the year compared to older and staple items from 2013 or earlier.

The $13.5 billion U.S. denim market grew 4 percent in 2016, highlighting its rebound from recent challenging times, according to The NPD Group.

Within the women’s category, jeans that launched at retailers within the past two years made up almost 70 percent of the units sold in 2016 and represented nearly all of the dollar gains for the year. Older product offerings from 2013 or earlier retained 19 percent of the units sold, but were responsible for more than a third of the dollar losses in 2016.

In contrast, most of the men’s jeans sold in 2016 were older products that launched at retail in 2013 or earlier–accounting for the majority of the dollar sales losses for the year. Merchandise introduced in 2016 was a much smaller portion of the men’s market, but generated almost three-quarters of the dollars gained.

“Jeans are representative of retail as a whole–newness and innovation drives growth while the basics maintain volume,” says Marshal Cohen, chief industry analyst, The NPD Group. “Denim manufacturers and retailers are realizing the importance of striking a balance between giving consumers the features they know and love, and introducing them to some new elements they didn’t know they needed.

“How many more of the same style jeans do women need? Why should men, who are less likely to gravitate to new and different product, change for the sake of change,” continues Cohen. “The denim market needs to find ways to break consumers of comfortable shopping habits with new product offerings that are worthy of both the change and the spend, ultimately driving the market forward into its rightful place of strength.”