Bi-annual	US dollars
1987-06-30	1321
1987-12-31	1385
1988-06-30	1417
1988-12-31	1509
1989-06-30	1546
1989-12-31	1405
1990-06-30	1516
1990-12-31	1525
1991-06-30	1401
1991-12-31	1360
1992-06-30	1204
1992-12-31	1100
1993-06-30	1263
1993-12-31	986
1994-06-30	1042
1994-12-31	932
1995-06-30	961
1995-12-31	973
1996-06-30	1478
1996-12-31	1251
1997-06-30	2023
1997-12-31	2325
1998-06-30	2194
1998-12-31	2594
1999-06-30	2606