Bi-annual	US dollars
1987-06-30	2704
1987-12-31	2872
1988-06-30	2601
1988-12-31	2311
1989-06-30	2158
1989-12-31	1782
1990-06-30	1681
1990-12-31	1806
1991-06-30	1907
1991-12-31	2013
1992-06-30	2097
1992-12-31	1823
1993-06-30	2216
1993-12-31	2235
1994-06-30	2142
1994-12-31	2639
1995-06-30	2081
1995-12-31	2738
1996-06-30	2084
1996-12-31	2869
1997-06-30	3625
1997-12-31	4033
1998-06-30	3941
1998-12-31	4291
1999-06-30	2961