Bi-annual	US dollars
1987-06-30	4465
1987-12-31	4757
1988-06-30	4999
1988-12-31	4840
1989-06-30	3389
1989-12-31	2536
1990-06-30	2403
1990-12-31	1704
1991-06-30	2388
1991-12-31	2129
1992-06-30	3585
1992-12-31	3304
1993-06-30	5058
1993-12-31	4830
1994-06-30	5926
1994-12-31	6601
1995-06-30	7698
1995-12-31	8140
1996-06-30	8679
1996-12-31	9310
1997-06-30	9997
1997-12-31	11529
1998-06-30	12940
1998-12-31	10942
1999-06-30	10319