Bi-annual US dollars 1987-06-30 11 1987-12-31 13 1988-06-30 14 1988-12-31 18 1989-06-30 23 1989-12-31 18 1990-06-30 30 1990-12-31 15 1991-06-30 18 1991-12-31 11 1992-06-30 4 1992-12-31 14 1993-06-30 8 1993-12-31 15 1994-06-30 8 1994-12-31 2 1995-06-30 3 1995-12-31 6 1996-06-30 2 1996-12-31 2 1997-06-30 15 1997-12-31 39 1998-06-30 20 1998-12-31 20 1999-06-30 16