A homeowner took out a $20-$year fixed$-$rate mortgage of $$170,000.$ The mortgage was taken out $10$ years ago at a rate of $6\mathrm{.}7$ percent. If the homeowner refinances, the charges will be $$3,000.$ What is the highest interest rate at which it would be beneficlal to refinance the mortgage?

Note: Do not round Intermedlate calculations. Enter your answer as a percent rounded to $2$ decimal places.