The board of trustees is authorized to use interest earnings on investments of the system in excess of normal requirements, as determined by the actuary, to provide an annual cost of living adjustment payable monthly for members retired at least two years, in an amount not to exceed three percent of the original benefit. Such benefits shall be paid only when funds are available from this source, and payments shall be made in such manner and in such amount as is determined by the board of trustees, based on the funds available.
La. Consolidated Public Retirement § 11:2073