540. Where the revenue from taxes and compensations contemplated in section 537, during the fiscal period begun in 1979, hereinafter called “taxation revenue”, does not reach an amount equal to at least one-half of the total revenue provided for in the budget for that fiscal period, hereinafter called “general revenue”, the provisional accounts may be increased in the same proportion as the difference between the taxation revenue and one-half of the general revenue bears to the taxation revenue.