A firm has only two funding sources, debt and equity. Their percentage of debt is $18\%,$ their tax rate is $23\mathrm{.}7\%,$ and their pretax cost of debt is $4\mathrm{.}37\%.$ If the required return on their equity is $8\mathrm{.}98\%,$ then what is their weighted average cost of capital? State your answer as a percentage with two decimal places $($i$.$e$.,13\mathrm{.}21,$ not $\mathrm{.}1321).$