Vanessa wants to retire in 25 years with enough saved to be able to withdraw $5,000 monthly for 20 years. She has already accumulated $48,000 in her investment account. Assume that the rate of interest is 4.8% compounded annually for the 25 years of her contributions, and changes to 3.6% compounded monthly for the next 20 years. Determine what annual contributions she has to make for the next 25 years in order to meet her objective.