Zimmer Biomet Corporation in Warsaw Indiana produces orthopedic devices (artificial hips, knees, and shoulders). The WACC at the end of 2017 when the corporate tax rate was 35%, was 8.73%. President Trumps new tax plan lowers the corporate tax rate to 21% in 2018. Zimmer Biomets Board of Directors has decided that the want to keep the WACC the same in 2018 by changing the Debt to Equity ratio. Assume: Rd = 0.08, Re = 0.13, and the original debt to equity ratio (in 2017) was 0.5. What does the new, 2018, Debt to Equity ratio need to be?