Bi-annual US dollars 1987-06-30 6 1987-12-31 25 1988-06-30 2 1988-12-31 4 1989-06-30 3 1989-12-31 2 1990-06-30 2 1990-12-31 4 1991-06-30 3 1991-12-31 4 1992-06-30 6 1992-12-31 8 1993-06-30 6 1993-12-31 6 1994-06-30 15 1994-12-31 14 1995-06-30 68 1995-12-31 12 1996-06-30 9 1996-12-31 22 1997-06-30 8 1997-12-31 7 1998-06-30 12 1998-12-31 7 1999-06-30 9