Bi-annual US dollars 1987-06-30 11 1987-12-31 17 1988-06-30 142 1988-12-31 14 1989-06-30 60 1989-12-31 77 1990-06-30 47 1990-12-31 15 1991-06-30 41 1991-12-31 50 1992-06-30 59 1992-12-31 52 1993-06-30 42 1993-12-31 59 1994-06-30 17 1994-12-31 61 1995-06-30 56 1995-12-31 64 1996-06-30 37 1996-12-31 53 1997-06-30 90 1997-12-31 67 1998-06-30 147 1998-12-31 45 1999-06-30 61