Bi-annual US dollars 1987-06-30 21 1987-12-31 36 1988-06-30 41 1988-12-31 52 1989-06-30 23 1989-12-31 13 1990-06-30 44 1990-12-31 12 1991-06-30 19 1991-12-31 9 1992-06-30 17 1992-12-31 14 1993-06-30 11 1993-12-31 18 1994-06-30 51 1994-12-31 11 1995-06-30 5 1995-12-31 2 1996-06-30 113 1996-12-31 2 1997-06-30 22 1997-12-31 63 1998-06-30 80 1998-12-31 70 1999-06-30 8