The board of examiners for teachers may charge a fee of fifty cents for every duplicate certificate. The proceeds from such fees shall be deposited with the State Treasurer to be used by the board of examiners to cover the expense and labor of issuing duplicate certificates promptly and to pay the traveling expenses of the director of the board of examiners while in the discharge of his official duties. All disbursements of such fees shall be made only on vouchers approved by the State Superintendent of Education. An itemized statement of such expenditures shall be kept and published in the annual report of the State Superintendent of Education.