A mechanical engineer must recommend an A/C system to a commercial building owner. The owner intends to own the building for at least 10 years. A conventional split system has a design life of 10 years, a cost of $50,000, and annual operating costs of $15,000. A chilled water system has a design life of 10 years, an initial cost of $65,000, and annual operating costs of $13,000. Using a rate of return of 10%, determine the present worth index of the incremental investment up to the chilled water system. Express your answer to two decimal places.