The measured value of the length of a simple pendulum is \( 20 \, \text{cm} \) with \( 2 \, \text{mm} \) accuracy. The time for \( 50 \) oscillations was measured to be \( 40 \, \text{seconds} \) with \( 1 \, \text{seconds} \) resolution. From these measurements, the accuracy in the measurement of acceleration due to gravity is \( N\% \). The value of \( N \) is: