Most U.S. banks charge their customers fees for the use of automated teller machines, and those fees have risen to "shocking heights" during the past five years, according to a new report.

The survey of 168 banks in nine states and the District of Columbia, which was conducted for the U.S. Public Research Group, found the number of banks charging depositors a fee to use a network ATM has increased from 40 percent in 1986 to 78 percent.The report also said that the average fee for a network transaction increased by 29 percent, from 65 cents to 84 cents, and that the fee banks charged despositors to use an ATM owned by the bank rose 150 percent from 26 cents to 65 cents.

The study noted, however, that 22 percent of banks surveyed did not charge any ATM fees.

"Nationally, not only are banks raising ATM fees to shocking heights, but consumers have little choice but to pay, since 78 percent of banks now charge network ATM fees," said Ed Mierzwinski, a national consumer advocate for PIRG.

"What is particularly onerous is . . . if one in five banks can avoid charging ATM fees, why can't the rest?"

Virginia Stafford, a spokeswoman for the American Banking Association, said bank customers have shown they are willing to pay ATM fees because they are a fair price for convenience.

"ATMs allow banks to be open 24 hours a day, seven days a week," Stafford said. "They're at multiple locations and the customers have privacy and no I.D. problem. And many customers have indicated that they prefer both ATMs and (human) tellers."

Stafford added that the costs involved in a bank becoming part of an ATM network requires that it charge a customer who decides to use the service.

"But that fact that 22 percent of banks don't charge for use of ATMs is very good," Stafford said. "Customers should definitely take advantage of bank competition and look around. ATM fees really amount to a user fee, which can be avoided in most cases.

But Mierzwinski said consumers are increasingly at the mercy of "costly robot tellers as banks close their branches and shorten their hours."

"This is particularly unfair because ATMs were marketed as the free alternative to supposedly high-cost human tellers," Mierzwinski said.