18. The fee provided for in this Tariff shall be indexed on 1 April of each year on the basis of the cumulative rate of increase in the general Consumer Price Index for Canada for the period beginning on 31 December and ending on 31 December of the year preceding the indexing, as determined by Statistics Canada. The fee indexed in the prescribed manner shall be reduced to the nearest dollar where it contains a fraction of a dollar less than $0.50. It shall be increased to the nearest dollar where it contains a fraction of a dollar equal to or greater than $0.50.