Bi-annual	US dollars
1987-06-30	3981
1987-12-31	4523
1988-06-30	3994
1988-12-31	4280
1989-06-30	3539
1989-12-31	2519
1990-06-30	2025
1990-12-31	2176
1991-06-30	1735
1991-12-31	1935
1992-06-30	1966
1992-12-31	1551
1993-06-30	1660
1993-12-31	1401
1994-06-30	1603
1994-12-31	1863
1995-06-30	2012
1995-12-31	2368
1996-06-30	2279
1996-12-31	2749
1997-06-30	2800
1997-12-31	2785
1998-06-30	4613
1998-12-31	4576
1999-06-30	4486