It's not a secret that offering health insurance to your employees is continually getting more expensive. Now there's data that shows exactly how much more you're paying than in the past.

This year, the average cost of employer-sponsored health insurance is $6,896 for individual plans and $19,616 for family plans, according to a new survey of businesses released by the nonprofit Kaiser Family Foundation. That's a 47 percent increase for single plans and a 55 percent rise for family plans compared with 2008.

Employees contribute an average of $1,186, or 18 percent, of the total cost for individual plans. For family plans, the average worker contribution is $5,547, or 29 percent, an increase in cost of 65 percent from a decade ago.

Employer-sponsored plans benefit an estimated 152 million people in the U.S., according to the report.

"Health costs don't rise in a vacuum," Drew Altman, president and CEO of the Kaiser Family Foundation, said in a statement. "As long as out-of-pocket costs for deductibles, drugs, surprise bills, and more continue to outpace wage growth, people will be frustrated by their medical bills and see health costs as huge pocketbook and political issues." 

Since 2008, average premiums for family plans have grown more than twice as fast as workers' earnings (55 percent vs. 26 percent), the report found. Deductibles, or the amount of money a worker needs to pay out-of-pocket for claims, also have increased. The higher deductibles have helped keep premium increases "relatively low," the survey states, though it also questions whether the trend is sustainable.

Next year, people without health insurance will no longer have to pay a penalty fee, thanks to the new tax law passed in 2017. Some companies expect this change will prompt fewer people to sign on to their health insurance plans, according to the survey.