The authority shall submit annually to the executive head or designated officer or officers of each state a budget of its estimated expenditures for such year as may be required by the laws of that state for presentation to the legislature thereof. The total amount of the authority's budget of estimated expenditures shall be apportioned among the states in equal shares. Subject to appropriation by the legislatures of the states, the authority shall be provided with such funds by each of the states as are necessary to enable the authority to fulfill the powers and duties imposed upon and entrusted to it.