Section 135-67 - Assets of Retirement System(a) All of the assets of the Retirement System shall be credited according to the purpose for which they are held to one of two funds, namely, the annuity savings fund and the pension accumulation fund.(b) The annuity savings fund shall be the fund to which all members' contributions, and regular interest allowances thereon as provided for in G.S. 135-7(b), shall be credited. From this fund shall be paid the accumulated contributions of a member in accordance with G.S. 135-62, or 135-63.(c) Upon the retirement of a member, his accumulated contributions shall be transferred from the annuity savings fund to the pension accumulation fund. In the event that a retired former member should subsequently again become a member of the Retirement System as provided for in G.S. 135-60(c) or 135-71, any excess of his accumulated contributions at his date of retirement over the sum of the retirement allowance payments received by him since his date of retirement shall be transferred from the pension accumulation fund to the annuity savings fund and shall be credited to his individual account in the annuity savings fund.(d) The pension accumulation fund shall be the fund in which shall be accumulated contributions by the State and amounts transferred from the annuity savings fund in accordance with subsection (c) above, and to which all income from the invested assets of the Retirement System shall be credited. From this fund shall be paid retirement allowances and any other benefits provided for under this Article except payments of accumulated contributions as provided in subsection (b) above.(e) The regular interest allowance on the members' accumulated contributions provided for in G.S. 135-7(b) shall be transferred each year from the pension accumulation fund to the annuity savings fund.