Bi-annual US dollars 1987-06-30 150 1987-12-31 281 1988-06-30 259 1988-12-31 148 1989-06-30 212 1989-12-31 208 1990-06-30 403 1990-12-31 457 1991-06-30 431 1991-12-31 243 1992-06-30 344 1992-12-31 545 1993-06-30 684 1993-12-31 610 1994-06-30 517 1994-12-31 430 1995-06-30 493 1995-12-31 216 1996-06-30 493 1996-12-31 423 1997-06-30 561 1997-12-31 155 1998-06-30 332 1998-12-31 428 1999-06-30 378