Bi-annual	US dollars
1987-06-30	2037
1987-12-31	1902
1988-06-30	2101
1988-12-31	1906
1989-06-30	1942
1989-12-31	1990
1990-06-30	1927
1990-12-31	1789
1991-06-30	1978
1991-12-31	2025
1992-06-30	2761
1992-12-31	2209
1993-06-30	2474
1993-12-31	1961
1994-06-30	2108
1994-12-31	1758
1995-06-30	1756
1995-12-31	1735
1996-06-30	1588
1996-12-31	2208
1997-06-30	2683
1997-12-31	1864
1998-06-30	1564
1998-12-31	1780
1999-06-30	1802