Bi-annual US dollars 1987-06-30 6 1987-12-31 47 1988-06-30 55 1988-12-31 5 1989-06-30 36 1989-12-31 55 1990-06-30 21 1990-12-31 8 1991-06-30 8 1991-12-31 19 1992-06-30 4 1992-12-31 12 1993-06-30 14 1993-12-31 15 1994-06-30 2 1994-12-31 8 1995-06-30 11 1995-12-31 8 1996-06-30 8 1996-12-31 36 1997-06-30 28 1997-12-31 25 1998-06-30 43 1998-12-31 42 1999-06-30 2