Bi-annual US dollars 1987-06-30 35 1987-12-31 19 1988-06-30 19 1988-12-31 16 1989-06-30 14 1989-12-31 19 1990-06-30 24 1990-12-31 108 1991-06-30 32 1991-12-31 37 1992-06-30 29 1992-12-31 17 1993-06-30 36 1993-12-31 22 1994-06-30 46 1994-12-31 28 1995-06-30 31 1995-12-31 37 1996-06-30 28 1996-12-31 41 1997-06-30 52 1997-12-31 163 1998-06-30 107 1998-12-31 155 1999-06-30 91