During the recession, consumers and businesses put off buying new vehicles. When the economy improved, many rushed out to replace the clunkers they’d been driving, driving sales up year after year.

“The market is pretty saturated right now,” said Jessica Caldwell, an analyst with Edmunds.com. She noted that there were now 1.26 vehicles on the road for every licensed driver, more than ever.

The downward sales trend is the latest challenge for the industry. Tariffs could be imposed on cars made in Mexico and Canada if the Trump administration negotiates major changes to the North American Free Trade Agreement. Manufacturers are also trying to push ahead with self-driving and electric vehicles even as it remains unclear how many they will be able to sell, and when.

The effect of rising fuel prices is also a question mark. Though still low by the standards of recent years, prices at the pump were $2.49 a gallon for regular gas on Wednesday compared with $2.35 a year ago, according to AAA.

The seven-year stretch of growth from 2010 to 2016 is the longest since the infancy of the automobile nearly a century ago, according to the automotive publisher WardsAuto. It was born out of one of the industry’s darkest periods: the deep recession that prompted federally backed bankruptcy reorganizations of General Motors and Chrysler. At the low point, 2009, new-car sales plunged to fewer than 11 million a year.