Actual solar cell performance after 5yrs

Cobalt power systems installed a PV system on my house almost 5 years ago.  The cells were made by Sun Power and the inverter is a Sunny Boy.  Before starting the project, Cobalt power gave me an estimate of the amount of power the cells would produce.  It is interesting to see that over the past 5 years my cells produced 95% of the expected power, i.e., Cobalt's estimated real world performance reasonably accurately.

Cobalt power estimated 8307 KWh/year, falling at 0.5% a year as my cells degrade.  My actual 5yr production was 39105 KWh.  Not bad.