Bi-annual	US dollars
1987-06-30	4078
1987-12-31	4202
1988-06-30	4342
1988-12-31	3918
1989-06-30	3792
1989-12-31	3549
1990-06-30	3844
1990-12-31	3602
1991-06-30	3548
1991-12-31	3403
1992-06-30	3606
1992-12-31	3962
1993-06-30	3663
1993-12-31	3212
1994-06-30	3113
1994-12-31	2954
1995-06-30	2558
1995-12-31	2307
1996-06-30	1723
1996-12-31	1851
1997-06-30	2084
1997-12-31	2001
1998-06-30	1662
1998-12-31	1539
1999-06-30	1164