Bi-annual	US dollars
1987-06-30	768
1987-12-31	847
1988-06-30	744
1988-12-31	870
1989-06-30	1009
1989-12-31	1161
1990-06-30	1132
1990-12-31	1017
1991-06-30	997
1991-12-31	981
1992-06-30	1163
1992-12-31	1006
1993-06-30	1140
1993-12-31	1049
1994-06-30	974
1994-12-31	943
1995-06-30	533
1995-12-31	498
1996-06-30	440
1996-12-31	440
1997-06-30	494
1997-12-31	431
1998-06-30	444
1998-12-31	413
1999-06-30	342