99. From the fiscal year beginning in 1972 of each municipal corporation and school board in the territory of which at the beginning of such fiscal year, immoveables of Hydro-Québec or any of its subsidiaries are situated, entry of which on the roll is prohibited by section 16, such immoveables, as long as they exist, shall be subject to the real estate taxes respectively established as follows in relation to those of the municipal or school fiscal year which began in 1971:(a) the school taxes shall be equal to those for the school fiscal year begun in 1971 for that begun in 1972 and afterwards shall decrease annually at the rate of 5% of the initial amount;
(b) for the next ten fiscal years the municipal taxes shall be equal to the total of those of the municipal fiscal year beginning in 1971 and the compensations in lieu thereof for such fiscal year;
(c) from the municipal fiscal year beginning in 1982, the municipal taxes on dams and power-houses established in accordance with paragraph b shall decrease annually at the rate of 3% of the initial amount and those on the other immoveables whose entry on the roll is prohibited by section 16, established in the same manner, shall decrease annually at the rate of 5% of the initial amount.