Also you can use the hardcore table like function to find the derivative if you do not use the interpolation function:
(*[[All, 2]]* takes all rows and pick up the second column only/ time step = 1*)
ListConvolve[{1, -1}, data[[All, 2]]]
assuming data is
data = {{0, 0.1425`}, {1, 0.1425`}, {2, 0.1425`}, ..., {99, 0.523363636`}}