Bi-annual US dollars 1987-06-30 5 1987-12-31 6 1988-06-30 5 1988-12-31 5 1989-06-30 8 1989-12-31 6 1990-06-30 5 1990-12-31 6 1991-06-30 6 1991-12-31 6 1992-06-30 8 1992-12-31 8 1993-06-30 11 1993-12-31 13 1994-06-30 9 1994-12-31 8 1995-06-30 14 1995-12-31 19 1996-06-30 20 1996-12-31 21 1997-06-30 5 1997-12-31 5 1998-06-30 7 1998-12-31 5 1999-06-30 0