An amount equal to not more than one cent for each inhabitant of the continental United States as determined by the last preceding decennial census may be appropriated each year in the District of Columbia Appropriation Act for the National Capital Planning Commission to use for the payment of its expenses and for the acquisition of land the Commission may acquire under section 8731 of this title for the purposes named, including compensation for the land, surveys, ascertainment of title, condemnation proceedings, and necessary conveyancing. The appropriated amounts shall be paid from the revenues of the District of Columbia and the general amounts of the Treasury in the same proportion as other expenses of the District of Columbia.