 Those changes permitted the investment program to modernize, resulting in investment income and gains of more than $13.6 billion over the past twenty-five years.This growth in assets has been achieved during a time when the fund has earned 10.0 percent per year.During this same period, funding by the State of Illinois fell far short of both the actuarial and statutory requirements, missing an opportunity for SURS to significantly reduce, if not eliminate, its unfunded liability.