Bi-annual US dollars 1987-06-30 313 1987-12-31 377 1988-06-30 264 1988-12-31 134 1989-06-30 298 1989-12-31 171 1990-06-30 396 1990-12-31 149 1991-06-30 225 1991-12-31 110 1992-06-30 468 1992-12-31 241 1993-06-30 192 1993-12-31 285 1994-06-30 290 1994-12-31 451 1995-06-30 423 1995-12-31 394 1996-06-30 244 1996-12-31 413 1997-06-30 501 1997-12-31 235 1998-06-30 637 1998-12-31 338 1999-06-30 311