Bi-annual US dollars 1987-06-30 152 1987-12-31 164 1988-06-30 153 1988-12-31 155 1989-06-30 172 1989-12-31 185 1990-06-30 195 1990-12-31 206 1991-06-30 198 1991-12-31 250 1992-06-30 276 1992-12-31 221 1993-06-30 117 1993-12-31 236 1994-06-30 256 1994-12-31 280 1995-06-30 282 1995-12-31 287 1996-06-30 329 1996-12-31 288 1997-06-30 298 1997-12-31 378 1998-06-30 362 1998-12-31 328 1999-06-30 238