The cash price of a $1\mathrm{.}5-$year Treasury bill is $102\mathrm{.}8$ at present. The bond pays an annual coupon of $6$ which is paid on a semi$-$annual basis. The $\mathrm{.}5$ year and $1$ year zero rates have already been calculated as $0\mathrm{.}012425$ and $0\mathrm{.}014778.$ Calculate the one$-$and$-$a$-$half$-$year zero rate $($Hint: The bonds' face values would be $100.)$

Report your answer in decimal format rounded to four decimal places. $($It is suggested that you carry six decimal places in your calculations, but round your final answer to four decimal places.$)$