Bi-annual US dollars 1987-06-30 700 1987-12-31 736 1988-06-30 779 1988-12-31 756 1989-06-30 794 1989-12-31 718 1990-06-30 710 1990-12-31 805 1991-06-30 832 1991-12-31 947 1992-06-30 946 1992-12-31 939 1993-06-30 983 1993-12-31 814 1994-06-30 715 1994-12-31 715 1995-06-30 654 1995-12-31 653 1996-06-30 618 1996-12-31 582 1997-06-30 477 1997-12-31 475 1998-06-30 535 1998-12-31 411 1999-06-30 624