As used in this Section and Section 1-160, the "implementation date" under this Section means the earliest date upon which the board of a retirement system authorizes members of that system to begin participating in accordance with this Section, as determined by the board of that retirement system. Each of the retirement systems subject to this Section shall endeavor to make such participation available as soon as possible after the effective date of this Section and shall establish an implementation date by board resolution.
For the purposes of this Section, "consumer price index-w" means the index published by the Bureau of Labor Statistics of the United States Department of Labor that measures the average change in prices of goods and services purchased by Urban Wage Earners and Clerical Workers, United States city average, all items, 1982-84 = 100. The new amount resulting from each annual adjustment shall be determined by the Public Pension Division of the Department of Insurance and made available to the boards of the retirement systems and pension funds by November 1 of each year.
40 ILCS 5/1-161