Bi-annual US dollars 1987-06-30 0 1987-12-31 2 1988-06-30 7 1988-12-31 5 1989-06-30 0 1989-12-31 0 1990-06-30 2 1990-12-31 2 1991-06-30 2 1991-12-31 2 1992-06-30 0 1992-12-31 0 1993-06-30 0 1993-12-31 0 1994-06-30 0 1994-12-31 2 1995-06-30 2 1995-12-31 3 1996-06-30 5 1996-12-31 2 1997-06-30 7 1997-12-31 3 1998-06-30 2 1998-12-31 5 1999-06-30 5