Bi-annual	US dollars
1987-06-30	1920
1987-12-31	1515
1988-06-30	1494
1988-12-31	1220
1989-06-30	1573
1989-12-31	1327
1990-06-30	1735
1990-12-31	1696
1991-06-30	2157
1991-12-31	2901
1992-06-30	3406
1992-12-31	3165
1993-06-30	4970
1993-12-31	6321
1994-06-30	6548
1994-12-31	7104
1995-06-30	7494
1995-12-31	9612
1996-06-30	9976
1996-12-31	12010
1997-06-30	13414
1997-12-31	13742
1998-06-30	12468
1998-12-31	11324
1999-06-30	8751