The cemetery association shall place at least one hundred dollars for each cemetery lot sold into the perpetual care trust fund. Such funds shall be paid by the cemetery association to the trustees of the perpetual care trust fund, who shall invest the funds under the same conditions and restrictions as trust funds are invested under section 30-3201. If any lots are sold on contract, thirty percent of all payments received on the contract shall be paid to the trustee or trustees of the perpetual care trust fund until the entire payments required by this section are made.