Bi-annual US dollars 1987-06-30 13 1987-12-31 8 1988-06-30 14 1988-12-31 5 1989-06-30 42 1989-12-31 10 1990-06-30 16 1990-12-31 17 1991-06-30 18 1991-12-31 4 1992-06-30 10 1992-12-31 3 1993-06-30 17 1993-12-31 16 1994-06-30 37 1994-12-31 31 1995-06-30 24 1995-12-31 23 1996-06-30 19 1996-12-31 22 1997-06-30 35 1997-12-31 36 1998-06-30 32 1998-12-31 28 1999-06-30 74