(2) "Effective rate of interest": For a fiscal year concluding no later than June 30, 2014, the interest rate for all or any part of a fiscal year that is determined by the board based on factors including the system's past and expected investment experience; historical and expected fluctuations in the market value of investments; the desirability of minimizing volatility in the effective rate of interest from year to year; and the provision of reserves for anticipated losses upon sales, redemptions, or other disposition of investments and for variations in interest experience; except that for the purpose of determining the accumulated normal contributions used in calculating retirement annuities under Rule 2 of Section 15-136, the effective rate of interest shall be determined by the State Comptroller rather than the board. For a fiscal year concluding no later than June 30, 2014, the State Comptroller shall determine the effective rate of interest to be used for this purpose using the factors listed above, and shall certify to the board and the Commission on Government Forecasting and Accountability the rate to be used for this purpose for fiscal year 2006 as soon as possible after the effective date of this amendatory Act of the 94th General Assembly, and for each fiscal year thereafter no later than the January 31 immediately preceding the start of that fiscal year. For a fiscal year that begins on or after July 1, 2014, the effective rate of interest for a given fiscal year shall be equal to the interest rate of 30-year United States Treasury bonds as of the beginning of that given fiscal year, plus 75 basis points. This effective rate of interest shall not be used in determining the prescribed rate of interest as defined in paragraph (1) of this Section.