Bi-annual US dollars 1987-06-30 3 1987-12-31 38 1988-06-30 10 1988-12-31 5 1989-06-30 9 1989-12-31 10 1990-06-30 17 1990-12-31 8 1991-06-30 2 1991-12-31 7 1992-06-30 2 1992-12-31 11 1993-06-30 11 1993-12-31 7 1994-06-30 11 1994-12-31 11 1995-06-30 22 1995-12-31 16 1996-06-30 20 1996-12-31 24 1997-06-30 23 1997-12-31 21 1998-06-30 22 1998-12-31 123 1999-06-30 71