Bi-annual US dollars 1987-06-30 11 1987-12-31 17 1988-06-30 14 1988-12-31 13 1989-06-30 9 1989-12-31 32 1990-06-30 26 1990-12-31 14 1991-06-30 0 1991-12-31 157 1992-06-30 8 1992-12-31 26 1993-06-30 56 1993-12-31 102 1994-06-30 160 1994-12-31 103 1995-06-30 35 1995-12-31 37 1996-06-30 42 1996-12-31 12 1997-06-30 30 1997-12-31 41 1998-06-30 22 1998-12-31 43 1999-06-30 28