The growth in employer premiums has typically been in the double digits every year. That runaway growth has meant problems for workers and the economy. Over the past few decades, employers began dropping health coverage, and premium increases eroded income growth. Some talked about the employer benefit system as a doomed anachronism. The new trend, if it holds, looks a lot more sustainable.

Health economists disagree about the precise mix of factors underlying the slowdown, but most think it has been caused by some combination of a weak economy and shifts in medical practice away from expensive hospitalizations and drugs. Over all, medical spending since 2009 had grown at a per capita rate of about 3 percent. People with employer-provided insurance make up the largest group in the market, so it stands to reason that the slowdown would start pulling down premiums eventually.

“What we’ve really seen over the last 10 years is moderation and stability in the group market,” said Drew Altman, Kaiser’s president. “If I was a corporate C.E.O., I’d have a lot more to worry about now than my health benefits.”

The huge growth in spending before the slowdown didn’t even tell the whole story. Over the same period, employers began shifting more of the costs of health insurance to their workers. The amounts workers were asked to pay for premiums went up, as did the number of plans that included high deductibles. The actual cost of insuring workers was growing even faster than premiums. (The Kaiser report is full of great charts mapping these changes over time.)