Trying to calculate rate of degradation, can someone please check my math?

Hi! Hope these posts are ok to make. Math was never my strong suit so I just want to check what I think is a pretty decent degradation rate for my 3 year old EV.

I can’t charge at home and have had to rely on public charging, which until recently was mostly DCFC at ~50 kw. Occasionally (a few times a year), I might do a couple cycles of DCFC at a faster rate while road-tripping.

With that in mind, my math shows my 77kwh battery (82kwh usable) has degraded 1.82% in terms of experience and actual range lost.

The way I figured this was to calculate that my most recent charge from 36-73% delivered a little over 28 kWh, which means a 37% charge is 28kwh.

This makes 10% = ~7.56kwh

7.56 x 10 = ~75.6kwh.

75.6kwh is 98.18% of 77.

While the full rate of degradation is above 8%, the usable degradation is less than 2% over 3 years of almost exclusively DCFC. That’s not too bad, right?