Bi-annual US dollars 1987-06-30 16 1987-12-31 17 1988-06-30 22 1988-12-31 29 1989-06-30 43 1989-12-31 31 1990-06-30 23 1990-12-31 23 1991-06-30 24 1991-12-31 6 1992-06-30 10 1992-12-31 14 1993-06-30 17 1993-12-31 10 1994-06-30 8 1994-12-31 16 1995-06-30 16 1995-12-31 17 1996-06-30 9 1996-12-31 9 1997-06-30 15 1997-12-31 31 1998-06-30 12 1998-12-31 17 1999-06-30 24