A 2.700x10⁻² M solution of glycerol (C₃H₈O₃) in water is at 20.0°C. The sample was created by dissolving a sample of C₃H₈O₃ in water and then bringing the volume up to 1.000 L. It was determined that the volume of water needed to do this was 998.8 mL. The density of water at 20.0°C is 0.9982 g/mL. Calculate the concentration of the glycerol solution in percent by mass.