Bi-annual US dollars 1987-06-30 10 1987-12-31 11 1988-06-30 12 1988-12-31 5 1989-06-30 0 1989-12-31 2 1990-06-30 0 1990-12-31 0 1991-06-30 0 1991-12-31 0 1992-06-30 91 1992-12-31 80 1993-06-30 77 1993-12-31 50 1994-06-30 114 1994-12-31 94 1995-06-30 156 1995-12-31 186 1996-06-30 222 1996-12-31 193 1997-06-30 185 1997-12-31 163 1998-06-30 42 1998-12-31 116 1999-06-30 6