WASHINGTON — Despite a long recovery and record streak of job growth, the share of Americans moving to a new location continued a steady decline in 2017, reaching a new post-World War II low, an indicator of a less mobile workforce that reflects both an aging society and economic problems facing younger workers.

The decline marked the fifth straight year in which the share of the population moving dropped. In 2017, the number fell to 11 percent, according to the Census Bureau. The level was nearly twice as high in 1985, 20 percent, but has fallen steadily, except for occasional cyclical zigzags, for the last three decades.

For decades, high rates of mobility sharply distinguished the U.S. from other developed economies in Europe and Japan. The decline in mobility is due partly to what has become a less-dynamic and fluid American labor market, some economists believe.

The decline also reflects social and demographic factors such as an aging population and declining birth rates; older people tend to stay put and starting families often motivates people to go out on their own.

But economics has pushed the trend: Even though the job fortunes of young adults have improved after several difficult years following the Great Recession, many are still living in their parents’ homes or stuck in apartments with multiple roommates.

Stricter requirements for mortgages and large student debts may be keeping some from homeownership. But high prices, particularly in larger urban centers favored by young adults, also play a role. Builders have tended to bank on more-profitable, higher-priced houses or luxury apartments, and that’s helped exacerbate a shortage of affordable homes in many cities.

“I’ve been waiting now for a long time for these young people to get out of their parents’ basement,” said William Frey, a Brookings Institution demographer who compiled and analyzed the census statistics, which cover the period from March 2016 to March 2017 and also include a sliver of foreign migration in the U.S.

Part of the slowing mobility could be a lifestyle issue, Frey said. “Maybe a little bit of inertia based on having not followed the norm of earlier generations.” Still, given all the economic improvements, he added, “it’s stunning to see the overall mobility the lowest ever.”

In recent decades, the rate at which firms create new jobs has fallen; so has the rate at which they eliminate positions, said Steven J. Davis, a professor at the University of Chicago Booth School of Business. Both trends discourage workers from moving.

“Lower gross job destruction rates mean less impetus from one’s labor market experience to pick up and move locations,” he said. “At the same time, lower gross job creation rates mean less opportunity to find a job in a new location.”

Some analysts say the recently signed GOP tax overhaul is expected to increase economic growth next year. That could give a boost to mobility and a lift to the housing market.

don.lee@latimes.com