Bi-annual US dollars 1987-06-30 21 1987-12-31 85 1988-06-30 48 1988-12-31 141 1989-06-30 57 1989-12-31 42 1990-06-30 42 1990-12-31 35 1991-06-30 75 1991-12-31 82 1992-06-30 70 1992-12-31 65 1993-06-30 57 1993-12-31 40 1994-06-30 71 1994-12-31 48 1995-06-30 67 1995-12-31 50 1996-06-30 42 1996-12-31 41 1997-06-30 43 1997-12-31 54 1998-06-30 73 1998-12-31 67 1999-06-30 99