Bi-annual US dollars 1987-06-30 3 1987-12-31 6 1988-06-30 2 1988-12-31 9 1989-06-30 6 1989-12-31 6 1990-06-30 14 1990-12-31 31 1991-06-30 29 1991-12-31 41 1992-06-30 46 1992-12-31 26 1993-06-30 321 1993-12-31 58 1994-06-30 26 1994-12-31 34 1995-06-30 122 1995-12-31 39 1996-06-30 70 1996-12-31 147 1997-06-30 150 1997-12-31 82 1998-06-30 82 1998-12-31 90 1999-06-30 110