Bi-annual US dollars 1987-06-30 87 1987-12-31 123 1988-06-30 43 1988-12-31 43 1989-06-30 84 1989-12-31 45 1990-06-30 26 1990-12-31 8 1991-06-30 60 1991-12-31 75 1992-06-30 259 1992-12-31 206 1993-06-30 203 1993-12-31 61 1994-06-30 179 1994-12-31 236 1995-06-30 199 1995-12-31 198 1996-06-30 204 1996-12-31 168 1997-06-30 215 1997-12-31 173 1998-06-30 155 1998-12-31 145 1999-06-30 139