Bi-annual US dollars 1987-06-30 13 1987-12-31 9 1988-06-30 27 1988-12-31 49 1989-06-30 20 1989-12-31 21 1990-06-30 42 1990-12-31 17 1991-06-30 8 1991-12-31 9 1992-06-30 10 1992-12-31 8 1993-06-30 5 1993-12-31 1 1994-06-30 5 1994-12-31 3 1995-06-30 6 1995-12-31 6 1996-06-30 26 1996-12-31 27 1997-06-30 8 1997-12-31 3 1998-06-30 7 1998-12-31 2 1999-06-30 2