Bi-annual US dollars 1987-06-30 789 1987-12-31 617 1988-06-30 810 1988-12-31 640 1989-06-30 1014 1989-12-31 947 1990-06-30 996 1990-12-31 1480 1991-06-30 1649 1991-12-31 1674 1992-06-30 1481 1992-12-31 1153 1993-06-30 1092 1993-12-31 1252 1994-06-30 940 1994-12-31 1392 1995-06-30 1783 1995-12-31 2031 1996-06-30 2068 1996-12-31 2556 1997-06-30 2589 1997-12-31 3677 1998-06-30 3826 1998-12-31 4438 1999-06-30 4880