Although most natural potassium nuclei are stable $)$ or ${?}^{41}K(6\mathrm{.}7\%)$ nuclei, about $0\mathrm{.}0117\%$ are radioactive ${?}^{40}K$ nuclei, which have a half$-$life of $1\mathrm{.}26$ billion years. What fraction of all the potassium nuclei in your body will undergo radioactive decay in the next $1\mathrm{.}29-$year period?

fraction $=$