You have a 20 year annuity, depositing $500 per year, earning 6.1%, compounded annually. However, at the end of 20 years you have accumulated $17,000. Concerned, you ask your accountant and she informs you that the amount deposited each year was changed after the 13th period. What was the new deposit amount for the last 7 years? Make your answer positive, 2 decimal places.