Bi-annual US dollars 1987-06-30 2 1987-12-31 0 1988-06-30 0 1988-12-31 0 1989-06-30 12 1989-12-31 0 1990-06-30 0 1990-12-31 0 1991-06-30 2 1991-12-31 4 1992-06-30 6 1992-12-31 8 1993-06-30 15 1993-12-31 40 1994-06-30 42 1994-12-31 69 1995-06-30 49 1995-12-31 43 1996-06-30 51 1996-12-31 62 1997-06-30 47 1997-12-31 46 1998-06-30 48 1998-12-31 48 1999-06-30 52