EA Prerequisite Minimum Energy Performance

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.