Bank credit card rates average about 1 percentage point less today than they did in 1986, with the best deals in New England and the worst in the West, the American Bankers Association reported.

The ABA's 1987 Retail Credit Report showed the average rate on a bank card carrying a fixed interest rate varied between 17.24 percent and 17.98 at the midpoint of this year. In the first half of last year, the range was from 18.26 percent to 19.34 percent, the report said.

The lower rates represent the average offered by banks with $50 to $100 million in assets, while the higher number was the average for banks with under $50 million in assets. Other types of banks had averages in between.

Banks with credit cards carrying a variable interest rate charged averages this year ranging from 14.59 percent to 16.49 percent, the report said.

New England had the lowest rates of any region at 16.33 percent, followed by a region consisting of Arkansas, Louisiana, Oklahoma and Texas at 16.4 percent.

The region with the highest rates included the mountain states of Arizona, Colorado, Montana, Nevada, New Mexico, Utah and Wyoming at 19.21 percent.

No matter what rates are charged, credit cards are becoming more popular, the ABA said. The number of MasterCard holders increased 9 percent since last year to 74 million, while the number of Visa holders rose 7 percent to 99 million.

Mark Gerwing, incoming chairman of the banking group's Bank Card Division, said the study indicates rates are becoming increasingly competitive.

"Today consumers have more choices," he said. "Besides lower rates, banks are offering more flexible credit card programs, either through variable or tiered pricing or through affinity programs, which are becoming one of the fastest growing segments in the bank card industry."

Affinity cards are offered through an agreement between a card issuer and an organization that markets the card to members. Interest charges ranged in mid-1987 from 16.89 percent to 17.65 percent, again depending on the size of the bank involved.