Bi-annual	US dollars
1987-06-30	2074
1987-12-31	2057
1988-06-30	1946
1988-12-31	1698
1989-06-30	1617
1989-12-31	1543
1990-06-30	1371
1990-12-31	1443
1991-06-30	1088
1991-12-31	1255
1992-06-30	1604
1992-12-31	1435
1993-06-30	1745
1993-12-31	1587
1994-06-30	2167
1994-12-31	2492
1995-06-30	2235
1995-12-31	3354
1996-06-30	3056
1996-12-31	3393
1997-06-30	4134
1997-12-31	4205
1998-06-30	4315
1998-12-31	5205
1999-06-30	4447