The general equation fo exponential formula is,

Assume t = 0 for year 2019. So for t = 0, t = y = 103126.
Substitute values in the equation to detemine the value of a.

For year 2021, the value of t is 1 and value of y is 103856.
Substitute the values in the formula to determine the value of b.

So exponential equation is,

Here, t is time from year 2019.