Bi-annual US dollars 1987-06-30 15 1987-12-31 13 1988-06-30 12 1988-12-31 16 1989-06-30 22 1989-12-31 29 1990-06-30 14 1990-12-31 33 1991-06-30 34 1991-12-31 35 1992-06-30 29 1992-12-31 42 1993-06-30 32 1993-12-31 31 1994-06-30 28 1994-12-31 33 1995-06-30 30 1995-12-31 34 1996-06-30 31 1996-12-31 29 1997-06-30 22 1997-12-31 25 1998-06-30 20 1998-12-31 18 1999-06-30 2