Bi-annual US dollars 1987-06-30 261 1987-12-31 332 1988-06-30 418 1988-12-31 231 1989-06-30 490 1989-12-31 468 1990-06-30 767 1990-12-31 546 1991-06-30 512 1991-12-31 540 1992-06-30 725 1992-12-31 497 1993-06-30 506 1993-12-31 377 1994-06-30 549 1994-12-31 627 1995-06-30 698 1995-12-31 656 1996-06-30 987 1996-12-31 596 1997-06-30 719 1997-12-31 847 1998-06-30 922 1998-12-31 724 1999-06-30 618