I'm currently completing the form for the above prerequisite to achieve the credit for EA Credit Optimize Energy Performance under Case 2, Option 2. Benchmark against historical data (0-14 points).
In order to obtain the percent improvement over historical data, the credit states "List annualized normalized source energy use intensity for three or more years historical data".
I have added 4 years of historical source EUI data for the building (as calculated on Energy Star Portfolio) but the % improvement indicates a 77% improvement. I am unable to determine how the form calculated such a large improvement. From what I am able to see, normalized source energy use intensity (GJ/sq m) figure is made up of the sum of the 4 years historical source EUI data.