An experiment is performed to obtain the value of acceleration due to gravity $g$ by using a simple pendulum of length $L$. In this experiment time for $100$ oscillations is measured by using a watch of $1$ second least count and the value is $90.0$ seconds. The length $L$ is measured by using a meter scale of least count $1$ mm and the value is $20.0$ cm. The error in the determination of $g$ would be: