If it seems like your paycheck is mysteriously shrinking every year, it's probably true and it's certainly not a mystery as health insurance costs continue to climb steadily.

(William Thomas Cain/Getty Images)

"Our latest report finds a continuing increase in healthcare premium costs for employees, with an emphasis on shifting costs for family members, spouses and dependents, going up at an even higher rate than for employees," said Julie Stone, a senior consultant at Towers Watson Management.

"Nearly 50 percent of employers are increasing the cost for dependents at a higher rate or faster rate than employees, and  here is also a large number of organizations that have implemented the spouse surcharge when the spouse doesn't have coverage elsewhere," Stone said.

So how much more do workplace benefits cost, on average?

"Costs have gone up for the last couple of years for employers in the neighborhood of 4 to 4½ percent," Stone said. "But employees are picking up a good share of that, with the average employee increase over the past five years being 5 percent a year. That may not sound like a lot but it's twice the CPI, it's a lot more than people's salaries are going up, so it's pretty significant from a paycheck perspective."

To try and help control costs, she said "many of our employers are implementing incentives to incent healthy behaviors, to incent weight management and tobacco cessation, but you have to be aware of these programs and participate to see any savings."

Even though health insurance costs are going up, the rate they are rising is slowing down.

Stone believes this is due to the still sluggish economy, but also "the movement of several brand-name drugs to generics over the last year or two, that actually has a really significant impact. Several of those are highly utilized and have brought costs down dramatically."

Even as costs continue to rise, she stressed, "many employers realize that their business success is dependent on having a healthy workforce so it's a financial issue, but it's a business issue too."