Bi-annual US dollars 1987-06-30 0 1987-12-31 0 1988-06-30 9 1988-12-31 16 1989-06-30 8 1989-12-31 10 1990-06-30 10 1990-12-31 12 1991-06-30 8 1991-12-31 9 1992-06-30 11 1992-12-31 2 1993-06-30 14 1993-12-31 16 1994-06-30 28 1994-12-31 56 1995-06-30 32 1995-12-31 37 1996-06-30 44 1996-12-31 50 1997-06-30 43 1997-12-31 41 1998-06-30 52 1998-12-31 43 1999-06-30 36