The tax deduction for credit card interest is gone. Yet fewer credit card holders are paying their balances in full.

About 61 percent of us carried revolving balances in 1988, and 65 percent did in 1989. If you're making just the easy-to-scrape-up minimum payment listed on your monthly statement, your pocketbook is taking a hard hit over the long haul, says Changing Times, The Kiplinger Magazine.On a credit card with an 18 percent annual interest rate - equal to a 1.5 percent monthly periodic rate - approximately half of each payment that exceeds $10 is interest and half pays down principal. Assuming you made no other charges, a $500 purchase paid off one minimum payment at a time would cost almost $800 by the time you paid it off 75 months later. By raising the monthly payment to $20, you'd pay off the $500 debt 44 months sooner and pay the bank $177 less in interest.

You fall deeper into debt when you keep paying the minimum balance due while making additional purchases with your credit card. Add $200 in charges every month to the original $500 purchase while making only a 3 percent minimum monthly payment and you'll reach a $2,500 credit limit in a year. Pay that down by the minimum payment method and you send the bank more than $2,750 in interest over 161/2 years.