Bi-annual US dollars 1987-06-30 16 1987-12-31 17 1988-06-30 17 1988-12-31 7 1989-06-30 37 1989-12-31 26 1990-06-30 3 1990-12-31 62 1991-06-30 60 1991-12-31 19 1992-06-30 40 1992-12-31 76 1993-06-30 12 1993-12-31 65 1994-06-30 42 1994-12-31 33 1995-06-30 40 1995-12-31 44 1996-06-30 42 1996-12-31 0 1997-06-30 13 1997-12-31 5 1998-06-30 58 1998-12-31 67 1999-06-30 22