Natural gas utilities for Northern Illinois and Chicago are making their business customers a little happier than last year, but they still rank below many others in the Midwest, according to a customer satisfaction study by J.D. Power and Associates.

Nicor Gas, which serves northern Illinois, rose 15 points on the index, and now ranks 13th among 21 Midwestern gas utilities. Peoples Gas, which serves Chicago, rose 3 points, but remained toward the bottom, landing at No. 20. Both came in below the Midwest average.

Nationwide, the satisfaction level was essentially flat. But customers expressed less satisfaction with communications, particularly regarding energy-saving programs that could help businesses cut their bills.

For the first time since the study began six years ago, communication issues trumped price as the least satisfactory aspect of service.

J.D. Power, of Westlake, Calif., bases its index on online interviews with more than 7,600 businesses that spend between $200 and $50,000 monthly on natural gas. The utilities are measured on billing and payment, corporate citizenship, price, communications, customer service and field service.