Hubbard Industries is an all$-$equity firm whose shares have an expected return of $9\mathrm{.}9\%.$ Hubbard does a leveraged recapitalization, issuing debt and repurchasing stock, until its debt$-$equity ratio is $0\mathrm{.}54.$ Due to the

increased risk, shareholders now expect a return of $14\mathrm{.}5\%.$ Assuming there are no taxes and Hubbard's debt is risk$-$free, what is the interest rate on the debt?

The interest rate is

$\%.($Round to two decimal places.$)$