Bi-annual US dollars 1987-06-30 16 1987-12-31 36 1988-06-30 19 1988-12-31 9 1989-06-30 153 1989-12-31 13 1990-06-30 19 1990-12-31 6 1991-06-30 6 1991-12-31 13 1992-06-30 10 1992-12-31 6 1993-06-30 42 1993-12-31 41 1994-06-30 49 1994-12-31 119 1995-06-30 99 1995-12-31 60 1996-06-30 165 1996-12-31 154 1997-06-30 163 1997-12-31 158 1998-06-30 155 1998-12-31 32 1999-06-30 25