Bi-annual US dollars 1987-06-30 0 1987-12-31 0 1988-06-30 0 1988-12-31 0 1989-06-30 0 1989-12-31 0 1990-06-30 0 1990-12-31 0 1991-06-30 0 1991-12-31 6 1992-06-30 19 1992-12-31 12 1993-06-30 14 1993-12-31 16 1994-06-30 31 1994-12-31 0 1995-06-30 3 1995-12-31 0 1996-06-30 2 1996-12-31 0 1997-06-30 0 1997-12-31 3 1998-06-30 55 1998-12-31 22 1999-06-30 3