A company's ROA and ROE are constant as $6\%$ and $13\%$ respectively and these two variables are defined as net income dividend by the previous year's total assets and equity respectively. The company always pays out $20\%$ of its net income as dividend. What is the maximum growth rate in firm size $($total assets$)$ if the source for asset increase is retained earnings and additional debt that keep the debt ratio constant. $($please report the answer as a decimal number and keep THREE decimal places such as $0\mathrm{.}018)?$