Bi-annual	US dollars
1987-06-30	7235
1987-12-31	7014
1988-06-30	6333
1988-12-31	5339
1989-06-30	6754
1989-12-31	6216
1990-06-30	4934
1990-12-31	4475
1991-06-30	4076
1991-12-31	4387
1992-06-30	4518
1992-12-31	4116
1993-06-30	5448
1993-12-31	4260
1994-06-30	3833
1994-12-31	4443
1995-06-30	4395
1995-12-31	4904
1996-06-30	4778
1996-12-31	4955
1997-06-30	5635
1997-12-31	6019
1998-06-30	7399
1998-12-31	8075
1999-06-30	8583