KANSAS CITY, Mo. -- The average cost of employer-paid benefits received by employees increased from $18,489 in 2005 to $21,527 in 2006, according to a study of 400 U.S. companies.

The U.S. Chamber of Commerce said in a new report that medical benefits accounted for the largest share of employee benefits costs at 12.1 percent of companies' total payroll costs.

Looking at the cost of benefits another way, the Employee Benefit Research Institute said Americans in 2006 received a gross total of $2.33 trillion in major employee benefit programs -- an increase of nearly 50 percent over 2000 -- and employers spent $1.42 trillion of that total on mandatory and voluntary employee benefit programs.

According to the Chamber of Commerce study, retirement benefits accounted for 10.4 percent of benefit costs, and paid time off for vacations, holidays and other time-off plans represented 9.8 percent.

The Chamber said companies in metropolitan areas paid about $3,600 more in medical benefits and $4,400 more in retirement benefits than companies in nonmetro areas.

When looked at from the Employee Benefit Research Institute's macro perspective, the amount paid in retirement benefits exceeded the cost of health benefits. Retirement benefit payments in 2006 accounted for $1.17 trillion, or half of the total benefit costs.

According to the institute, health-benefit payments totaled $1.01 trillion, or 43.5 percent of total 2006 benefit payments, of which 60 percent was paid by private group health insurance plans and 39.6 percent by Medicare.

The report also said other benefit programs, including unemployment insurance, workers' compensation, group life insurance, disability and veterans' benefits, represented 6.4 percent of total benefit payments in 2006.

Many studies show employees value their benefits as much as their base compensation. Randel Johnson, a chamber vice president, said benefits packages were a competitive tool to attract and keep workers. Such studies also helped businesses know what other companies were offering.

The EBRI study also found individuals paid $655.6 billion into benefit plans in 2006. Personal payments included contributions to Social Security, private-sector retirement plans and health benefits.