Bi-annual US dollars 1987-06-30 443 1987-12-31 508 1988-06-30 582 1988-12-31 1159 1989-06-30 772 1989-12-31 1345 1990-06-30 668 1990-12-31 386 1991-06-30 491 1991-12-31 551 1992-06-30 502 1992-12-31 612 1993-06-30 869 1993-12-31 439 1994-06-30 540 1994-12-31 548 1995-06-30 557 1995-12-31 623 1996-06-30 536 1996-12-31 330 1997-06-30 635 1997-12-31 482 1998-06-30 398 1998-12-31 829 1999-06-30 1985