(1) Service by an employee rendered since becoming a member;

(2) Service rendered prior to becoming a member but (A) subsequent to January 1, 1926, by an employee of the State or (B) subsequent to January 1, 1928, by an employee of any county;

(3) Service as an employee of the federal government where the function carried on by the government has been transferred to the State or any county, or where the employee has been transferred to the federal government and subsequently retransferred to the State or any county;

(4) Service rendered by an employee in the office of the delegate to Congress from Hawaii, or service rendered by an employee in the office of a representative or a senator to Congress from the State; provided that (A) the employee was a member of the system immediately preceding the time the employee renders such service; (B) the employee reenters the service of the State or county within one year after termination of such service; and (C) the employee has, to the satisfaction of the board of trustees, waived the employee's right to any credit under the Civil Service Retirement Act (5 U.S.C.A. 2251) based upon such service; provided further that credit for such service shall not exceed eight years;

(5) Service as an employee of the Hawaii territorial guard;

(6) Service while engaged in professional improvement pursuant to an approved leave of absence for such purpose, with or without pay;

(7) Service between the years 1941 and 1947 with federal defense agencies, where the employee was employed by the government before the wartime service, went into defense work at the direction of the employee's employer, and returned to government service at the end of the wartime service; provided that these circumstances shall be verified by evidence satisfactory to the board of trustees;

(8) Service, not exceeding four years, in the military service of the United States during the period 1941-1949 rendered by an employee who was employed by the Territory or county prior to the employee's induction into the military and who subsequently returned to employment of the Territory or county following the employee's discharge;

(9) Service rendered prior to becoming a member as a full-time employee at the Leahi Hospital or Pahala Hospital, now known as Ka'u General Hospital, Puunene Hospital, Waimea Hospital, Waimea, Kauai, Haliimaile Dispensary, and Paia Hospital and Pioneer Mill Hospital;

(10) Service rendered prior to becoming a member as a full-time sheriff or deputy sheriff in the office of the sheriff;

(11) The period of time when a member was absent from work because of injuries incurred within the scope of the member's employment and who has received workers' compensation benefits prior to July 1, 1967;

(12) Service rendered as an employee of the legislature during any legislative session;

(13) Service as a school cafeteria manager or worker if paid by the State regardless of the source of funds from which paid; provided that twelve months' service shall be credited for the time such a person was working on a nine-month schedule during a school year.