Bi-annual	US dollars
1987-06-30	6410
1987-12-31	6533
1988-06-30	6032
1988-12-31	6107
1989-06-30	5928
1989-12-31	5479
1990-06-30	4473
1990-12-31	4108
1991-06-30	3768
1991-12-31	3564
1992-06-30	3665
1992-12-31	3541
1993-06-30	3963
1993-12-31	3853
1994-06-30	4134
1994-12-31	3824
1995-06-30	4241
1995-12-31	4242
1996-06-30	3859
1996-12-31	4552
1997-06-30	4530
1997-12-31	4557
1998-06-30	5804
1998-12-31	6536
1999-06-30	4202