Bi-annual US dollars 1987-06-30 18 1987-12-31 23 1988-06-30 24 1988-12-31 18 1989-06-30 22 1989-12-31 21 1990-06-30 21 1990-12-31 27 1991-06-30 24 1991-12-31 39 1992-06-30 40 1992-12-31 32 1993-06-30 30 1993-12-31 15 1994-06-30 17 1994-12-31 13 1995-06-30 13 1995-12-31 12 1996-06-30 11 1996-12-31 9 1997-06-30 5 1997-12-31 10 1998-06-30 3 1998-12-31 3 1999-06-30 5