Bi-annual US dollars 1987-06-30 6 1987-12-31 4 1988-06-30 5 1988-12-31 16 1989-06-30 6 1989-12-31 18 1990-06-30 16 1990-12-31 19 1991-06-30 13 1991-12-31 2 1992-06-30 27 1992-12-31 5 1993-06-30 6 1993-12-31 12 1994-06-30 15 1994-12-31 22 1995-06-30 13 1995-12-31 5 1996-06-30 3 1996-12-31 34 1997-06-30 43 1997-12-31 28 1998-06-30 23 1998-12-31 98 1999-06-30 80