Bi-annual	US dollars
1987-06-30	1024
1987-12-31	1523
1988-06-30	1434
1988-12-31	1423
1989-06-30	1510
1989-12-31	1563
1990-06-30	2401
1990-12-31	2474
1991-06-30	2395
1991-12-31	2266
1992-06-30	2181
1992-12-31	2153
1993-06-30	2102
1993-12-31	1877
1994-06-30	1576
1994-12-31	1378
1995-06-30	832
1995-12-31	673
1996-06-30	517
1996-12-31	394
1997-06-30	299
1997-12-31	220
1998-06-30	275
1998-12-31	175
1999-06-30	170