Hi Anmol,
That value is pretty close, is it possible that some of the data values were rounded early in the processing? Additionally, if you perform the linear fits across a different range, then you could get a different final answer (not clear whether it would be this different). This is the only data set I have, but I think there might be other data in the PlasmaPy distribution or from other plasma physics groups.
Best of luck in your studies,
David