The following Excel document contains observations on a stock price $($in dollars$)$ at the end of each of the $15$ consecutive weeks. But its calculations need to be corrected. What is the correct volatility per annum for the given stock?

$\backslash$table$[[1,$week,stock,log return,,,$],[2,1,33\mathrm{.}2,-0\mathrm{.}0089956,,,],[3,2,33\mathrm{.}5,-0\mathrm{.}0059524,$stdev,$0\mathrm{.}02883609,],[4,3,33\mathrm{.}7,0\mathrm{.}0059524,,,],[5,4,33\mathrm{.}5,0,$vol,$0\mathrm{.}55091277,],[6,5,33\mathrm{.}5,0\mathrm{.}01503788,,,],[7,6,33\mathrm{.}0,0\mathrm{.}0030349,,,],[8,7,32\mathrm{.}9,-0\mathrm{.}0030349,,,],[9,8,33\mathrm{.}0,0\mathrm{.}07550755,,,],[10,9,30\mathrm{.}6,0\mathrm{.}0098523,,,],[11,10,30\mathrm{.}3,0\mathrm{.}00330579,,,],[12,11,30\mathrm{.}2,0\mathrm{.}00331675,,,],[13,12,30\mathrm{.}1,-0\mathrm{.}0326826,,,],[14,13,31\mathrm{.}1,-0\mathrm{.}0285281,,,],[15,14,32\mathrm{.}0,0\mathrm{.}05789398,,,],[17,15,30\mathrm{.}2,,,,],[17,,,,,,]]$