Bi-annual US dollars 1987-06-30 18 1987-12-31 23 1988-06-30 17 1988-12-31 13 1989-06-30 84 1989-12-31 52 1990-06-30 3 1990-12-31 2 1991-06-30 2 1991-12-31 0 1992-06-30 0 1992-12-31 2 1993-06-30 0 1993-12-31 9 1994-06-30 5 1994-12-31 5 1995-06-30 11 1995-12-31 79 1996-06-30 2 1996-12-31 3 1997-06-30 2 1997-12-31 13 1998-06-30 15 1998-12-31 23 1999-06-30 27