(1) There is established in the state treasury the mental hospital earnings reserve fund. The fund shall be managed and invested by the endowment fund investment board according to law and the policies established by the state board of land commissioners. The fund shall consist of the following:
(a)  Earnings of the mental hospital permanent endowment fund, created to receive moneys from the insane asylum endowment provided in section 11 of the Idaho Admission Bill, 26 Stat. L. 215, ch. 656;
(b)  Proceeds of the sale of timber growing upon mental hospital lands;
(c)  Proceeds of leases of mental hospital lands;
(d)  Proceeds of interest charged upon deferred payments on mental hospital lands or timber on those lands; and
(e)  All other proceeds received from the use of mental hospital endowment lands and not otherwise designated for deposit in the mental hospital permanent endowment fund.
(2)  Moneys shall be distributed out of the mental hospital earnings reserve fund only to support the beneficiaries of the mental hospital endowment, including distributions by the state board of land commissioners to the mental hospital permanent endowment fund and the mental hospital income fund; provided, that funds shall not be appropriated by the legislature from the mental hospital earnings reserve fund except to pay for administrative costs incurred managing the assets of the mental hospital endowment including, but not limited to, real property and monetary assets.