Your parents invested money in a term deposit 15 years ago, and the current balance is $5,500. You will receive this amount on your 21st birthday, which is 5 years from now. The final 5-year term is locked at 3.25%.

Prior to that, they locked the money into a 5-year term deposit at 7.75%, then renewed it for another 5-year term at 6.25%, and finally locked it at 4.5%. How much did they initially deposit 15 years ago?

 Please round to 2 decimal places and DO NOT include $.