Bi-annual US dollars 1987-06-30 47 1987-12-31 30 1988-06-30 32 1988-12-31 38 1989-06-30 50 1989-12-31 52 1990-06-30 30 1990-12-31 41 1991-06-30 44 1991-12-31 56 1992-06-30 61 1992-12-31 71 1993-06-30 105 1993-12-31 74 1994-06-30 119 1994-12-31 158 1995-06-30 95 1995-12-31 76 1996-06-30 712 1996-12-31 659 1997-06-30 594 1997-12-31 556 1998-06-30 452 1998-12-31 419 1999-06-30 244