Specific gravity of alcohol and water mixture?

Three agricultural companies SK, YG, and AF are producing fermented corn solution (ethanol in water) for further processing into ethanol fuel. Each has supplied the following data for its product: Specific Gravity: .98201 at 17.00 degrees C, .97750 at 31.00 degrees C, .97920 at 21.60 degrees C. This data corresponds to SK, YG, and AF's data respectivly. Find the m percentage of alcohol in each product (to four decimal places). Decide how many stages of distillation would be required for each of these products to yield a final m concentration of ethanol of 85%.