Bi-annual	US dollars
1987-06-30	877
1987-12-31	1138
1988-06-30	1641
1988-12-31	1403
1989-06-30	1904
1989-12-31	2596
1990-06-30	2707
1990-12-31	3467
1991-06-30	2985
1991-12-31	3782
1992-06-30	4000
1992-12-31	2869
1993-06-30	3471
1993-12-31	1825
1994-06-30	1600
1994-12-31	1963
1995-06-30	2326
1995-12-31	2471
1996-06-30	3485
1996-12-31	2284
1997-06-30	2138
1997-12-31	2058
1998-06-30	1946
1998-12-31	2401
1999-06-30	1503