(a) From time to time the dollar amounts specified in sections 1-203 and 4-101(b)(7) must change, as provided in subsections (b) and (c), according to and to the extent of changes in the Consumer Price Index for Urban Wage Earners and Clerical Workers: United States City Average, All Items 1967=100, compiled by the Bureau of Labor Statistics, United States Department of Labor, (the "Index"). The Index for December, 1979, which was 230, is the Reference Base Index.

(b) The dollar amounts specified in sections 1-203 and 4- 101(b)(7), and any amount stated in the declaration pursuant to those sections, must change July 1 of each year if the percentage of change, calculated to the nearest whole percentage point, between the Index at the end of the preceding year and the Reference Base Index is ten percent or more, but

(i) The portion of the percentage change in the Index in excess of a multiple of ten percent must be disregarded and the dollar amounts shall change only in multiples of ten percent of the amounts appearing in this chapter on the date of enactment;

(ii) The dollar amounts must not change if the amounts required by this section are those currently in effect pursuant to this chapter as a result of earlier application of this section; and

(iii) In no event may the dollar amounts be reduced below the amounts appearing in this chapter on the date of enactment.

(c) If the Index is revised after December, 1979, the percentage of change pursuant to this section must be calculated on the basis of the revised Index. If the revision of the Index Changes the Reference Base Index, a revised Reference Base Index must be determined by multiplying the Reference Base Index then applicable by the rebasing factor furnished by the Bureau of Labor Statistics. If the Index is superseded, the Index referred to in this section is the one represented by the Bureau of Labor Statistics as reflecting most accurately changes in the purchasing power of the dollar for consumers.