 Powell is testifying before the Senate Banking Committee. The Fed chairman says he and his colleagues are encouraged by recent reports of cooling inflation, but they want to see more evidence before cutting interest rates. Some of that evidence could come later this week when the Labor Department reports on what happened to prices in June. The average interest rate on credit cards is approaching 23 percent, but that doesn't stop some people from relying on plastic. A new report shows revolving credit, which includes credit cards, grew at an annual rate of 6.3 percent in May.