You have been living in the house you bought 9 years ago for $400,000. At that time, you took out a loan for 80% of the house at a fixed rate 20-year loan at an annual stated rate of 7.5%. You have just paid off the 108th monthly payment. Interest rates have meanwhile dropped steadily to 4.5% per year, and you think it is finally time to refinance the remaining balance over the residual loan life. There is no prepayment penalty on the mortgage balance of the original loan, but other closing costs will be $4,000. How much will you save in payments each month if you refinance?