Bi-annual	US dollars
1987-06-30	1687
1987-12-31	1634
1988-06-30	1417
1988-12-31	2094
1989-06-30	1439
1989-12-31	2435
1990-06-30	2293
1990-12-31	2381
1991-06-30	2043
1991-12-31	2316
1992-06-30	2217
1992-12-31	2185
1993-06-30	4032
1993-12-31	4288
1994-06-30	4276
1994-12-31	3623
1995-06-30	3299
1995-12-31	3686
1996-06-30	4914
1996-12-31	3284
1997-06-30	4216
1997-12-31	4679
1998-06-30	2993
1998-12-31	3897
1999-06-30	4434