A client owes the IRS $20,000 in taxes, due today. In lieu of payment today, the IRS will allow your client to make 36 monthly payments of $628.44, with first payment due one month from today. Therefore, the implied interest rate being charged is ______% APR compounded monthly.

(We need to solve for r in the following equation:

Since there is no closed-form solution, you can solve using a financial calculator, or by trial-an-error. Use a calculator - its much quicker and accurate!

Note that the solution found on your calculator will be a monthly rate (if you enter the number of months in 'N'), so you need to multiply that by 12 to get final answer as an APR.)

(Enter the answer as, for example, "4.56" rounded to the nearest basis point, or hundredth of a percent. DO NOT enter the '%' symbol)