Bi-annual US dollars 1987-06-30 10 1987-12-31 23 1988-06-30 36 1988-12-31 38 1989-06-30 28 1989-12-31 34 1990-06-30 45 1990-12-31 29 1991-06-30 36 1991-12-31 13 1992-06-30 10 1992-12-31 9 1993-06-30 8 1993-12-31 6 1994-06-30 8 1994-12-31 25 1995-06-30 0 1995-12-31 19 1996-06-30 17 1996-12-31 3 1997-06-30 20 1997-12-31 15 1998-06-30 2 1998-12-31 2 1999-06-30 0