Bi-annual US dollars 1987-06-30 90 1987-12-31 57 1988-06-30 78 1988-12-31 61 1989-06-30 45 1989-12-31 56 1990-06-30 78 1990-12-31 15 1991-06-30 16 1991-12-31 9 1992-06-30 11 1992-12-31 6 1993-06-30 6 1993-12-31 31 1994-06-30 28 1994-12-31 30 1995-06-30 80 1995-12-31 40 1996-06-30 16 1996-12-31 50 1997-06-30 18 1997-12-31 13 1998-06-30 22 1998-12-31 20 1999-06-30 9