I was recently discussing my experience with solar energy with a friend, and it led me to want to review the performance of my system. So I pulled the calendar year of data from the Enphase site, and compared it with your original forecast from December of 2014.
Your predicted output: 13,225 kw/yr
My actual output for 2016: 13,324.854
That’s a deviation of 0.75%, and in the good direction. Amazing!