Tex. Gov't Code § 813.404
For each month of membership, military, or equivalent membership service not previously credited in the retirement system, a member claiming credit in the elected class shall pay a contribution in an amount equal to the greater of:
Acts 1981, 67th Leg., p. 1876, ch. 453, Sec. 1, eff. Sept. 1, 1981. Renumbered from Vernon's Ann.Civ.St. Title 110B, Sec. 23.404 by Acts 1989, 71st Leg., ch. 179, Sec. 1, eff. Sept. 1, 1989.
Amended by Acts 1995, 74th Leg., ch. 297, Sec. 4, eff. Sept. 1, 1995.
Acts 2011, 82nd Leg., R.S., Ch. 1249 (S.B. 1664), Sec. 5, eff. September 1, 2011.