Rani owns and operates a small electronic repair shop. A new instrument, called Rapid Diagnosist, which facilitates faster diagnosis of the items to be repaired, has been marketed recently. Being technologically new, it is however expensive. Based on the past, the costs of such instruments decline fast. Rani predicts that Rapid Diagnosist would sell for $5,000 in the next 5 years. She decides to retain a fixed sum each year from annual profit to raise this capital 5 years hence. The retained sum will be invested regularly in the local bank at 6.5% annually compounded interest rate. How much should be retained each year?