Bi-annual US dollars 1987-06-30 47 1987-12-31 13 1988-06-30 51 1988-12-31 33 1989-06-30 26 1989-12-31 31 1990-06-30 30 1990-12-31 31 1991-06-30 31 1991-12-31 2 1992-06-30 2 1992-12-31 2 1993-06-30 3 1993-12-31 3 1994-06-30 5 1994-12-31 0 1995-06-30 0 1995-12-31 11 1996-06-30 3 1996-12-31 21 1997-06-30 111 1997-12-31 18 1998-06-30 3 1998-12-31 50 1999-06-30 14