Is the Adult Coloring Book Trend Coming to an End?

When TIME highlighted the adult coloring book trend last year, Barnes & Noble VP Alex Perruzzi acknowledged that the genre had accounted for a significant part of sales during the 2015 holiday season, and expected business to keep booming. “We’re going to hit a plateau,” he said. “But it’s going to last a while.”

A while seems to be nigh. In an earnings call on Thursday, CFO Allen Lindstrom explained a disappointing 2016 holiday season by noting the decline in sales of coloring books and artist supplies. Though adult coloring book sales were up overall in the U.S. in 2016—14 million books sold compared to 10 million in 2015—that increase mainly came earlier in the year. December sales were down by 2 million books year over year, according to NPD Bookscan.

The trend seems to have reached a point of saturation, with fewer newcomers checking it out, though devotees are still on board. At the New York International Toy Fair last month, a sales account manager for coloring book publisher Fox Chapel told Publishers Weekly, “Sales have slowed, but we don’t think the market will go away,” said Wendy Calta. Noting that diehard fans like to work on multiple books at a time, she said, “The key with coloring is variety.”

Still, the slump in overall interest has real consequences for Barnes & Noble. Analysts predicted a 1.6% decline in same-store sales last quarter, which ended Jan. 28. But they actually declined 8.3%, Bloomberg reports, making it the worst holiday quarter drop in more than a decade.

Adult coloring books may have given a much-needed boost to struggling retailers, but like any trend, it can’t last forever.