Bi-annual US dollars 1987-06-30 176 1987-12-31 185 1988-06-30 247 1988-12-31 221 1989-06-30 296 1989-12-31 147 1990-06-30 359 1990-12-31 214 1991-06-30 151 1991-12-31 138 1992-06-30 306 1992-12-31 183 1993-06-30 122 1993-12-31 170 1994-06-30 273 1994-12-31 185 1995-06-30 283 1995-12-31 186 1996-06-30 235 1996-12-31 223 1997-06-30 419 1997-12-31 178 1998-06-30 262 1998-12-31 18 1999-06-30 139