Bi-annual US dollars 1987-06-30 2 1987-12-31 2 1988-06-30 2 1988-12-31 2 1989-06-30 3 1989-12-31 0 1990-06-30 0 1990-12-31 0 1991-06-30 0 1991-12-31 2 1992-06-30 2 1992-12-31 2 1993-06-30 18 1993-12-31 6 1994-06-30 5 1994-12-31 23 1995-06-30 24 1995-12-31 9 1996-06-30 19 1996-12-31 14 1997-06-30 20 1997-12-31 28 1998-06-30 32 1998-12-31 12 1999-06-30 3