Bi-annual US dollars 1987-06-30 485 1987-12-31 568 1988-06-30 602 1988-12-31 535 1989-06-30 451 1989-12-31 481 1990-06-30 542 1990-12-31 457 1991-06-30 363 1991-12-31 357 1992-06-30 32 1992-12-31 1268 1993-06-30 1675 1993-12-31 2823 1994-06-30 747 1994-12-31 853 1995-06-30 778 1995-12-31 687 1996-06-30 1046 1996-12-31 752 1997-06-30 987 1997-12-31 1073 1998-06-30 3571 1998-12-31 2493 1999-06-30 3385