Bi-annual US dollars 1987-06-30 23 1987-12-31 25 1988-06-30 12 1988-12-31 7 1989-06-30 16 1989-12-31 15 1990-06-30 21 1990-12-31 21 1991-06-30 19 1991-12-31 11 1992-06-30 25 1992-12-31 11 1993-06-30 11 1993-12-31 7 1994-06-30 5 1994-12-31 5 1995-06-30 0 1995-12-31 2 1996-06-30 34 1996-12-31 0 1997-06-30 8 1997-12-31 3 1998-06-30 7 1998-12-31 7 1999-06-30 0