Bi-annual US dollars 1987-06-30 3193 1987-12-31 2610 1988-06-30 3663 1988-12-31 3922 1989-06-30 4060 1989-12-31 3636 1990-06-30 3755 1990-12-31 3834 1991-06-30 3321 1991-12-31 3515 1992-06-30 3515 1992-12-31 2625 1993-06-30 2966 1993-12-31 2134 1994-06-30 2339 1994-12-31 2482 1995-06-30 3472 1995-12-31 4147 1996-06-30 3847 1996-12-31 5919 1997-06-30 5714 1997-12-31 5614 1998-06-30 7371 1998-12-31 5816 1999-06-30 7299