Bi-annual US dollars 1987-06-30 11 1987-12-31 28 1988-06-30 9 1988-12-31 31 1989-06-30 11 1989-12-31 29 1990-06-30 19 1990-12-31 17 1991-06-30 0 1991-12-31 2 1992-06-30 0 1992-12-31 0 1993-06-30 2 1993-12-31 0 1994-06-30 37 1994-12-31 55 1995-06-30 100 1995-12-31 152 1996-06-30 182 1996-12-31 187 1997-06-30 216 1997-12-31 163 1998-06-30 48 1998-12-31 111 1999-06-30 98