For twelve years beginning with the year 1961, the general assembly shall appropriate for each year out of the general revenue fund, an amount not less than that produced annually at a tax rate of one cent on each one hundred dollars assessed valuation of the real and tangible personal property taxable by the state, for the exclusive purpose of providing a state park fund to be expended and used by the agency authorized by law to control and supervise state parks, and historic sites of the state, for the purposes of the acquisition, supervision, operation, maintenance, development, control, regulation and restoration of state parks and state park property, as may be determined by such agency; and thereafter the general assembly shall appropriate such amounts as may be reasonably necessary for such purposes.

The amount required to be appropriated by this section may be reduced to meet budgetary demands provided said appropriation is not less than that appropriated for the prior similar appropriation period.