Bi-annual	US dollars
1987-06-30	5732
1987-12-31	7084
1988-06-30	6960
1988-12-31	7901
1989-06-30	8531
1989-12-31	8046
1990-06-30	9376
1990-12-31	8490
1991-06-30	7704
1991-12-31	7591
1992-06-30	7741
1992-12-31	8169
1993-06-30	17413
1993-12-31	20317
1994-06-30	22077
1994-12-31	22848
1995-06-30	24788
1995-12-31	26039
1996-06-30	28658
1996-12-31	30020
1997-06-30	25112
1997-12-31	31634
1998-06-30	28616
1998-12-31	24452
1999-06-30	23497