Employees in the same positions they were in last year at this time are earning an average of 3.5% more than in the third quarter of 2014, says the ADP Research Institute’s new Workforce Vitality Report. Meanwhile, job switchers’ pay has risen 6.5%.

Even that big gap is narrower than earlier this year, the report shows. Back in the first quarter, for instance, staying put got you a tiny 1.9% pay bump over 12 months earlier, while changing jobs led to an average 8% raise.

The premium in pay for job changers is far bigger in some industries than in others, the report shows. Moving on to a new employer in education or health care paid only 0.4% more than staying in the same place. By contrast, in construction, job switchers’ wages shot up 19.6% in the first three quarters of 2015, versus a relatively modest 4.3% boost for construction workers who stayed put.

“As the economic recovery goes on, companies are having more trouble finding workers with enough of the right skills,” notes Ahu Yildirmaz, head of the ADP Research Institute. “The shortage, along with employers’ need to hold on to top talent, is finally being reflected in higher wages.”

After construction, the financial services industry has seen the biggest raises. Wall Street may be handing out smaller bonuses this year, but jumping to a new job boosts bankers’ pay by an average of 12.6%.

So does this mean that job hoppers are on to something, at least when it comes to making more money? Well, yes and no, partly depending on age. The older you are, the smaller the pay bump for moving to a new job — probably because many employees in their late 30s to late 50s have been working long enough that they’re already pretty well paid. Among younger employees, however, ADP’s researchers noticed two interesting trends.

First, Gen Y (ages 25 to 34) is in “the sweet spot,” says Yildirmaz. “Job changers in this demographic can still command an average increase of nearly 7%, but they can also get larger raises than other age groups without changing jobs.” The reason is that, as Boomers retire, people 25 to 34 “are moving up in the ranks and being rewarded with hefty raises.” Many Millennials have become skilled negotiators, she adds, and “employers need to retain them, so they’re willing to pay more.”

And second, if employees in their early 20s are hard to hold on to, there’s a good reason. The study found that people under 25 who switch jobs earn an average of 17.5% more year over year, almost four times the 4.5% average pay hike they’d get by staying.

Of course, that’s partly because “younger workers typically have a much lower base wage, so increases have more impact,” says Yildirmaz. Even so, and despite the long-term career risks of too much job hopping, she adds, “you can certainly see why they do it.”