Bi-annual US dollars 1987-06-30 6 1987-12-31 8 1988-06-30 2 1988-12-31 9 1989-06-30 6 1989-12-31 0 1990-06-30 5 1990-12-31 21 1991-06-30 31 1991-12-31 13 1992-06-30 13 1992-12-31 8 1993-06-30 14 1993-12-31 24 1994-06-30 49 1994-12-31 53 1995-06-30 65 1995-12-31 50 1996-06-30 33 1996-12-31 17 1997-06-30 8 1997-12-31 10 1998-06-30 27 1998-12-31 15 1999-06-30 27