A 21 percent interest rate might sound like a scheme thought up by the mob, but it is the average credit card rate for Americans.

According to a study by the credit card analyst CardHub, the average rate has gone up 2 percent since last year.

CardHub’s report states, “Credit card interest rates were higher across the board during the first three months of 2014 relative to the same period last year."

Credit card companies often get customers by advertising low or zero-percent teaser rates, but after that grace period is over, the price gouging begins.

All of this profit comes at little cost to big banks, which borrow money at almost zero-percent rates.

“I think credit card companies are essentially realizing that consumers are more focused on introductory rates," CardHub CEO Odysseas Papadimitriou told the New York Post. "So they are not paying much attention to what happens after the introductory rates."

Papadimitriou also warned about cash-advance "payday" loans, which start at high interest rates on the day a customer walks out with a loan.

According to ABC News, the average American family owes $8,400 on credit cards. Americans owe $1.7 trillion on credit cards, department store cards and auto loans.

Sometimes people sign up for credit cards with zero-percent teaser rates because they want to transfer all of their debt to the new card, but Good Morning America's financial correspondent Mellody Hobson says people should put their debt on the credit card that has the lowest annual percentage rate, not teaser rate.

Sources: New York Post, ABC News, CardHub