(a) Any member of the retirement system shall be entitled to receive up to ten years of creditable service for teaching service in school systems of other states in the United States, state supported independent school systems of the United States, schools operated by the Bureau of Indian Affairs of the United States Department of the Interior, public school systems of the Virgin Islands, Puerto Rico, Guam, and the District of Columbia, or American dependents' schools, provided that the member has first established five years of membership service credit in the public schools of Georgia or the University System of Georgia; provided, further, that such service credit shall be allowed on the basis of one year of credit for such service for each additional year of membership service in the public schools of Georgia or the University System of Georgia. A teacher desiring to establish credit for such service must pay employee and employer contributions which would have been paid to the retirement system on a salary comparable to his salary for such service, plus the applicable rate of interest, in accordance with regulations adopted by the board of trustees. Such contributions must be paid prior to retirement under this retirement system. For such service rendered prior to January 1, 1945, the rate of employee contributions shall be 5 percent and the rate of employer contributions shall be 6.83 percent. The rate of interest on such contributions shall be the applicable regular interest. No member who receives or who is entitled to receive a pension or annuity from any other state, county, or municipality, or federal retirement program excluding social security, shall receive creditable service for such service. The board of trustees shall promulgate rules and regulations to carry out this Code section.

(b) Any provisions of this Code section to the contrary notwithstanding, teachers who became members of the retirement system prior to April 1, 1966, shall be permitted to establish credit for a maximum of ten years of service in school systems of other states in the United States that permit retirement credit for teaching service rendered in Georgia public schools, by paying 8 percent of such out-of-state compensation that they received, plus applicable accumulated interest, in accordance with regulations adopted by the board of trustees. Such members may establish credit for one year of out-of-state service for each year of membership service in the public schools of Georgia or the University System of Georgia rendered after the first five years of membership service.