Bi-annual US dollars 1987-06-30 166 1987-12-31 247 1988-06-30 258 1988-12-31 264 1989-06-30 284 1989-12-31 314 1990-06-30 290 1990-12-31 152 1991-06-30 178 1991-12-31 207 1992-06-30 285 1992-12-31 191 1993-06-30 465 1993-12-31 291 1994-06-30 356 1994-12-31 535 1995-06-30 259 1995-12-31 319 1996-06-30 378 1996-12-31 146 1997-06-30 253 1997-12-31 288 1998-06-30 228 1998-12-31 238 1999-06-30 237