Bi-annual US dollars 1987-06-30 163 1987-12-31 204 1988-06-30 198 1988-12-31 174 1989-06-30 161 1989-12-31 119 1990-06-30 113 1990-12-31 110 1991-06-30 146 1991-12-31 148 1992-06-30 211 1992-12-31 248 1993-06-30 248 1993-12-31 216 1994-06-30 181 1994-12-31 178 1995-06-30 180 1995-12-31 149 1996-06-30 172 1996-12-31 183 1997-06-30 180 1997-12-31 244 1998-06-30 252 1998-12-31 331 1999-06-30 284