Jon Stark ,Inc. Has estimated the costs of debt and equity capital for various proportions of debt in its capital structure.

% of Debt	Cost of Debt	Cost of Equity
0%	-	13.0%
10%	5.4%	13.3
20%	5.6	13.8
30%	5.8	14.4
40%	6.3	15.2
50%	7.0	16.0
60%	8.2	17.0

Based on these estimates, determine the WACC of Jon Starks optimal capital structure. Answers should be rounded off to 4 decimal places.