Bi-annual	US dollars
1987-06-30	2572
1987-12-31	4380
1988-06-30	3957
1988-12-31	4768
1989-06-30	3116
1989-12-31	4220
1990-06-30	4602
1990-12-31	4814
1991-06-30	4417
1991-12-31	5908
1992-06-30	3178
1992-12-31	2986
1993-06-30	3154
1993-12-31	2471
1994-06-30	2694
1994-12-31	2646
1995-06-30	3094
1995-12-31	3825
1996-06-30	3746
1996-12-31	3872
1997-06-30	3678
1997-12-31	4026
1998-06-30	4768
1998-12-31	4238
1999-06-30	4336