Consumers overwhelmingly believe that Visa and MasterCard should disclose the $30 billion in hidden "interchange" fees they charge each year and consumers want Congress to do something about it, according to a new poll released by the Merchants Payments Coalition (MPC) that was conducted by Harris Interactive.

Nine out of 10 U.S. adults believe credit card companies should disclose how much they charge in interchange fees and how those fees are set. Consumers also want Congress to require credit card companies to be more forthcoming about their policies and practices.

The poll found the following results:

Interchange is a percentage of each transaction that Visa and MasterCard collect from retailers every time a credit or debit card is used to pay for a purchase. The fee varies with type of merchant, transaction and card, but averages close to 2 percent for most credit card and signature debit transactions.

According to MPC, Visa and MasterCard interchange fees totaled $30.7 billion in 2005, up 17 percent over 2004 and an 85 percent increase since 2001. The average family in the U.S. pays more than $300 each year in hidden interchange fees.

Unlike other fees that appear on the cardholder's monthly statement, credit card company rules make it virtually impossible to inform consumers how much they are paying in interchange fees. The Harris Interactive survey found that 68 percent of U.S. adults had never heard of the interchange fee.

Release of the poll comes as interest in the interchange issue is growing in Congress. Senate Banking, Housing and Urban Affairs Committee Chairman Christopher Dodd, D-Conn., said last month that he plans to hold a hearing on interchange as part of a series of hearings looking into credit card industry practices. The Senate Judiciary Committee and a House Energy and Commerce Committee subcommittee held interchange hearings last year.