Bi-annual US dollars 1987-06-30 2 1987-12-31 15 1988-06-30 15 1988-12-31 22 1989-06-30 28 1989-12-31 16 1990-06-30 9 1990-12-31 8 1991-06-30 13 1991-12-31 19 1992-06-30 27 1992-12-31 59 1993-06-30 33 1993-12-31 21 1994-06-30 40 1994-12-31 25 1995-06-30 45 1995-12-31 43 1996-06-30 36 1996-12-31 80 1997-06-30 72 1997-12-31 77 1998-06-30 32 1998-12-31 87 1999-06-30 16