Bi-annual	US dollars
1987-06-30	1817
1987-12-31	1704
1988-06-30	1583
1988-12-31	1658
1989-06-30	1631
1989-12-31	2082
1990-06-30	1910
1990-12-31	1773
1991-06-30	1622
1991-12-31	1745
1992-06-30	1916
1992-12-31	1559
1993-06-30	1705
1993-12-31	1546
1994-06-30	1464
1994-12-31	1427
1995-06-30	1018
1995-12-31	1030
1996-06-30	1074
1996-12-31	1274
1997-06-30	1710
1997-12-31	1306
1998-06-30	1467
1998-12-31	1587
1999-06-30	1317