Bi-annual US dollars 1987-06-30 79 1987-12-31 70 1988-06-30 41 1988-12-31 38 1989-06-30 40 1989-12-31 29 1990-06-30 21 1990-12-31 14 1991-06-30 16 1991-12-31 7 1992-06-30 6 1992-12-31 3 1993-06-30 2 1993-12-31 4 1994-06-30 8 1994-12-31 5 1995-06-30 6 1995-12-31 3 1996-06-30 6 1996-12-31 9 1997-06-30 7 1997-12-31 10 1998-06-30 25 1998-12-31 23 1999-06-30 20