There is authorized to be appropriated annually to the Department of State, out of any money in the Treasury not otherwise appropriated, such sums as may be necessary for the payment by the United States of its share of the expenses of the International Atomic Energy Agency as apportioned by the Agency in accordance with paragraph (D) of article XIV of the Statute of the Agency, and for all necessary salaries and expenses of the representatives provided for in section 2021 of this title