Bi-annual US dollars 1987-06-30 593 1987-12-31 460 1988-06-30 614 1988-12-31 629 1989-06-30 853 1989-12-31 439 1990-06-30 363 1990-12-31 316 1991-06-30 415 1991-12-31 316 1992-06-30 457 1992-12-31 830 1993-06-30 743 1993-12-31 822 1994-06-30 835 1994-12-31 616 1995-06-30 681 1995-12-31 673 1996-06-30 710 1996-12-31 789 1997-06-30 789 1997-12-31 694 1998-06-30 805 1998-12-31 429 1999-06-30 596