Bi-annual	US dollars
1987-06-30	2604
1987-12-31	2702
1988-06-30	2580
1988-12-31	2517
1989-06-30	2460
1989-12-31	2390
1990-06-30	2483
1990-12-31	1997
1991-06-30	1574
1991-12-31	1700
1992-06-30	2126
1992-12-31	1971
1993-06-30	2753
1993-12-31	3323
1994-06-30	3162
1994-12-31	4007
1995-06-30	3552
1995-12-31	3619
1996-06-30	4043
1996-12-31	4369
1997-06-30	4470
1997-12-31	5179
1998-06-30	6272
1998-12-31	7255
1999-06-30	7427