Bi-annual US dollars 1987-06-30 697 1987-12-31 715 1988-06-30 563 1988-12-31 687 1989-06-30 744 1989-12-31 764 1990-06-30 781 1990-12-31 849 1991-06-30 871 1991-12-31 869 1992-06-30 801 1992-12-31 515 1993-06-30 854 1993-12-31 2554 1994-06-30 2998 1994-12-31 3159 1995-06-30 3711 1995-12-31 4372 1996-06-30 4260 1996-12-31 4814 1997-06-30 4487 1997-12-31 6153 1998-06-30 6899 1998-12-31 6109 1999-06-30 5476