Section 5. Public school fund revenue. (1) Ninety-five percent of all the interest received on the public school fund and ninety-five percent of all rent received from the leasing of school lands and all other income from the public school fund shall be equitably apportioned annually to public elementary and secondary school districts as provided by law.
     (2) The remaining five percent of all interest received on the public school fund, and the remaining five percent of all rent received from the leasing of school lands and all other income from the public school fund shall annually be added to the public school fund and become and forever remain an inseparable and inviolable part thereof.