(b) For any judge who retires under K.S.A. 20-2608 or 20-2609, and amendments thereto, on or after July 1, 1975, the annuity shall be based on the final average salary of such judge as provided in this subsection. The final average salary of a judge who becomes permanently physically or mentally disabled and who is retired under K.S.A. 20-2608 or 20-2609, and amendments thereto, shall be determined as if such judge had retired on the date such judge became permanently physically or mentally disabled. The final average salary of a former judge whose service is terminated without retiring and who later retires under K.S.A. 20-2608, and amendments thereto, shall be determined as if such former judge had retired at the time such service was terminated. In the case of judges who retire on or after July 1, 1993, the final average salary shall mean the average highest annual salary paid to the judge for any three years of the last 10 years of service as a judge immediately preceding retirement or termination of employment, or if service as a judge is less than three years, then the final average salary shall be the average annual salary paid to the judge during the full period of service as a judge, or if service as a judge is less than one year, then the final average salary shall be computed by multiplying the amount of monthly salary such judge was receiving at the time of retirement by 12.