Bi-annual US dollars 1987-06-30 108 1987-12-31 140 1988-06-30 121 1988-12-31 96 1989-06-30 101 1989-12-31 148 1990-06-30 169 1990-12-31 131 1991-06-30 133 1991-12-31 159 1992-06-30 120 1992-12-31 80 1993-06-30 99 1993-12-31 108 1994-06-30 315 1994-12-31 110 1995-06-30 127 1995-12-31 144 1996-06-30 65 1996-12-31 118 1997-06-30 53 1997-12-31 100 1998-06-30 85 1998-12-31 73 1999-06-30 16