Appointments to the board shall be made for a period of three years.  Vacancies shall be filled by the council for the balance of the unexpired term.  A vacancy occurs when a member resigns, fails to qualify within fourteen days, dies, moves from Sioux City, or has unexcused (as determined by the board) absences of thirty percent or more of the board meetings within any twelve-month period.  No person may serve more than three consecutive full terms on the board. Full terms begin July 1st and end June 30th.  However, members whose terms have expired shall continue to serve until a successor is appointed by the city council.  (Ord. 92/U-360)