Bi-annual US dollars 1987-06-30 229 1987-12-31 211 1988-06-30 157 1988-12-31 80 1989-06-30 50 1989-12-31 0 1990-06-30 0 1990-12-31 0 1991-06-30 0 1991-12-31 0 1992-06-30 0 1992-12-31 23 1993-06-30 23 1993-12-31 25 1994-06-30 22 1994-12-31 30 1995-06-30 29 1995-12-31 47 1996-06-30 53 1996-12-31 56 1997-06-30 60 1997-12-31 69 1998-06-30 77 1998-12-31 73 1999-06-30 63