Three students $S_1, S_2$ and $S_3$ perform an experiment for determining the acceleration due to gravity (g) using a simple pendulum. They use different lengths of pendulum and record time for different number of oscillations. The observations are as shown in the table. (Least count of length $=0.1 \mathrm{~m}$, least count for time $=0.1 \mathrm{~s}$ )
If $\mathrm{E}_1, \mathrm{E}_2$ and $\mathrm{E}_3$ are the percentage errors in ' g ' for students 1,2 and 3 respectively, then the minimum percentage error is obtained by student no. $\_\_\_\_$ .