Bi-annual US dollars 1987-06-30 13 1987-12-31 13 1988-06-30 15 1988-12-31 14 1989-06-30 12 1989-12-31 10 1990-06-30 14 1990-12-31 8 1991-06-30 6 1991-12-31 9 1992-06-30 2 1992-12-31 3 1993-06-30 2 1993-12-31 7 1994-06-30 3 1994-12-31 5 1995-06-30 3 1995-12-31 3 1996-06-30 11 1996-12-31 3 1997-06-30 8 1997-12-31 15 1998-06-30 18 1998-12-31 8 1999-06-30 14