Bi-annual US dollars 1987-06-30 52 1987-12-31 40 1988-06-30 26 1988-12-31 9 1989-06-30 22 1989-12-31 13 1990-06-30 10 1990-12-31 29 1991-06-30 16 1991-12-31 13 1992-06-30 8 1992-12-31 20 1993-06-30 51 1993-12-31 27 1994-06-30 179 1994-12-31 111 1995-06-30 46 1995-12-31 57 1996-06-30 84 1996-12-31 110 1997-06-30 30 1997-12-31 247 1998-06-30 60 1998-12-31 47 1999-06-30 251