Bi-annual US dollars 1987-06-30 366 1987-12-31 413 1988-06-30 404 1988-12-31 385 1989-06-30 397 1989-12-31 432 1990-06-30 459 1990-12-31 465 1991-06-30 439 1991-12-31 555 1992-06-30 872 1992-12-31 630 1993-06-30 719 1993-12-31 610 1994-06-30 727 1994-12-31 767 1995-06-30 725 1995-12-31 755 1996-06-30 875 1996-12-31 697 1997-06-30 820 1997-12-31 874 1998-06-30 1042 1998-12-31 850 1999-06-30 653