The fair market value identified in section 11-4-7-1 of this chapter shall be subject to a "CPI adjustment" which shall be calculated on January 1, 2003, as a base year adjusted on January 1 in each year thereafter. Annually, the "fair market value" shall be adjusted to an amount equal to the "fair market value" multiplied by a fraction, the numerator of which is the "all items" "Consumer Price Index For Urban Consumers (1982-84 = 100)" for Chicago, Illinois, published by the United States department of labor's bureau of labor statistics ("CPI") for the month of December preceding the adjustment and the denominator of which is the CPI for the month of December 2002. If any index is calculated from a base different from the base period 1982-84 = 100, such index shall be converted to a base period of 1982-84 = 100 by use of a conversion factor supplied by said bureau of labor statistics. If the CPI is discontinued or replaced, such other governmental cost of living index or computation which replaces the CPI shall be used in order to obtain substantially the same result as would be obtained if the CPI had not been discontinued or replaced. (Ord. 0-2007-839, 12-13-2007)