Bob has just turned 32 years old and planning for his retirement at age 60. He plans to save $8,000 per year at the end of next 10 years. Bob wants to have retirement income of $65,000 per year for 25 years, with the first payment starting one year from the date he retires. How much must Bob save at the end of each year 11 to 28 in order to achieve his retirement goal? The interest rate is 7%.