A homeowner took out a 20-year, fixed-rate mortgage of $410,000. The mortgage was taken out 10 years ago at a rate of 5.60 percent. If the homeowner refinances, the charges will be $4,000. What is the highest interest rate at which it would be beneficial to refinance the mortgage? (Do not round intermediate calculations. Round your answer to 2 decimal places. Omit the "%" sign in your response.)
APR