Bi-annual US dollars 1987-06-30 0 1987-12-31 0 1988-06-30 0 1988-12-31 0 1989-06-30 0 1989-12-31 0 1990-06-30 2 1990-12-31 29 1991-06-30 29 1991-12-31 19 1992-06-30 4 1992-12-31 3 1993-06-30 9 1993-12-31 15 1994-06-30 15 1994-12-31 14 1995-06-30 14 1995-12-31 12 1996-06-30 14 1996-12-31 14 1997-06-30 13 1997-12-31 23 1998-06-30 8 1998-12-31 8 1999-06-30 2