Tammy wishes to save money to provide for her retirement. Beginning one month from now, she will begin depositing a fixed amount into a retirement savings account that will earn 10% compounded monthly. She will make 420 such deposits. Then, one year after making her final deposit, she will withdraw $75,000 annually for 20 years. The fund will continue to earn 10% compounded monthly. How much should the monthly deposits be for her retirement plan?