The survey, released Wednesday by the U.S. Bureau of Labor Statistics, found that for single coverage in which employee premium contributions are required, total monthly premiums average $399.96 for union plans, compared with $341.13 for plans covering nonunion employees.

Additionally, premium contributions made by union employees are, on average, much lower compared with those of nonunion employees. Among employers that require employees to pay a portion of the health insurance premium, union-represented employees, on average, pay a monthly premium of $62.45 for single coverage compared with a monthly average of $83.51 for nonunion employees.

In addition, only half of union-represented employees pay a portion of the premium for single coverage, while 81 percent of nonunion employees do so.

The same patterns hold true for family coverage. For example, in plans in which employee premium contributions are required, the total average monthly family premium for union-represented employees is $970.06, while the total premium for nonunion employees averages $953.13.

On average, nonunion employees pay $323.80 a month for family coverage, compared with $211.91 for union-represented employees. Ninety-three percent of nonunion employees pay a portion of the premium for family coverage, compared with 57 percent of union-employees.

The results are based on plan information as of March 2007 and on the responses of 8,256 employers.

Copies of the survey, “National Compensation Survey: Employee Benefits in Private Industry in the United States, March 2007,” are available at www.bls.gov.

Filed by Jerry Geisel of Business Insurance, a sister publication of Workforce Management. To comment, e-mail editors@workforce.com.