This metric is the percent reduction in emissions from the air travel, based on emitted CO2 (eCO2) through air travel by fiscal year. The difference between the given year eCO2 and the baseline FY14 eCO2 is divided by the baseline FY14 eCO2.  The data is from the GHG emissions report. Use the Second Nature website for the University of Illinois at Urbana-Champaign for data from 2016 onwards.