Average Rate on Credit Cards at 10-Year Low : * Interest: Ram Research says the figure has slipped below 18% for the first time since 1981, and experts say rates for the most credit-worthy customers will slip further.

A survey released Friday said the average credit card interest rate has fallen to its lowest level in a decade, and industry experts predicted that rates charged to some card customers will drop further this year.

Ram Research, a Frederick, Md.-based firm, said average credit card rates in January slipped to 17.95% from 18.18% in December, the first time they have dipped below 18% since 1981.

Robert McKinley, Ram president, said his firm surveyed 107 of the nation’s largest credit card issuers that control 93% of the market. However, McKinley said, rates charged by the 10 largest issuers, which account for 51% of the market, are 19.6%, virtually unchanged from last year.

The research company attributed the drop to political pressure on card issuers and a decline in overall interest rates, particularly the prime rate, which has dropped to 6.5% from 8% in October. Many variable-rate credit cards are pegged to the prime rate.

Other observers cautioned that the rates consumers pay on many credit card accounts have not fallen significantly.

“We don’t see a large movement downward,” said Geri Detweiller of Bankcard Holders of America, a Herndon, Va.-based consumer group. She said the average rate paid by most consumers in 1991 was 18.9%, primarily because the nation’s largest issuers, led by Citibank and Chase Manhattan Bank, haven’t lowered rates on their most widely used cards.

Another research firm, Bank Rate Monitor of West Palm Beach, Fla., said the average credit card rate in January was 18.8%, a barely perceptible drop from 18.86% a year ago. Bank Rate Monitor bases its figures on rates charged by the 100 largest banks and thrifts in the nation’s 10 biggest metropolitan areas.

Despite lack of agreement on the size of the decline in credit card rates, most analysts believe that rates will decline this year, at least for some cardholders. Kurt Peters, editor of Credit Card News in Chicago, said he considers it unlikely that banks will initiate across-the-board cuts in rates on their highly profitable Visas or MasterCards. But he said it is possible that banks will offer their best credit card customers lower rates to keep them from defecting to other low-rate cards.

“The banks can’t afford to sit by and let their customers go,” Peters said. “If there are defections, they will have to respond.”

This trend actually got under way last year when First National Bank of Chicago began offering its best customers a 14.4% rate, significantly below the 19.8% it charges on its most widely used card. The cut came as credit card rates came under increasing congressional scrutiny, leading to an unsuccessful movement to place a ceiling on credit card rates.

Analysts said that as credit card rates decline, people with poorer credit histories will find cards harder to get. “It goes hand-in-hand,” Peters said. “As rates come down, standards (for credit) get tighter.”