The energy of a system as a function of time $t$ is given as $E(t)=A^2 \exp (-a t)$, where $a=0.2 s^{-1}$. The measurement of $A$ has an error of $1.25 \%$. If the error in the measurement of time is $1.50 \%$, the percentage error in the value of $E(t)$ at $t=5 s$ is
