Bi-annual US dollars 1987-06-30 439 1987-12-31 474 1988-06-30 408 1988-12-31 447 1989-06-30 502 1989-12-31 589 1990-06-30 462 1990-12-31 486 1991-06-30 556 1991-12-31 753 1992-06-30 799 1992-12-31 795 1993-06-30 545 1993-12-31 256 1994-06-30 241 1994-12-31 178 1995-06-30 162 1995-12-31 129 1996-06-30 104 1996-12-31 43 1997-06-30 135 1997-12-31 44 1998-06-30 42 1998-12-31 50 1999-06-30 115