Bi-annual	US dollars
1987-06-30	921
1987-12-31	1340
1988-06-30	1317
1988-12-31	1271
1989-06-30	1228
1989-12-31	1450
1990-06-30	1509
1990-12-31	1449
1991-06-30	1354
1991-12-31	1061
1992-06-30	1248
1992-12-31	1697
1993-06-30	1496
1993-12-31	1751
1994-06-30	2519
1994-12-31	2202
1995-06-30	1570
1995-12-31	1640
1996-06-30	2543
1996-12-31	2179
1997-06-30	2043
1997-12-31	2884
1998-06-30	3516
1998-12-31	4506
1999-06-30	4313