Bi-annual US dollars 1987-06-30 106 1987-12-31 108 1988-06-30 148 1988-12-31 157 1989-06-30 143 1989-12-31 194 1990-06-30 199 1990-12-31 228 1991-06-30 92 1991-12-31 97 1992-06-30 89 1992-12-31 138 1993-06-30 162 1993-12-31 161 1994-06-30 221 1994-12-31 261 1995-06-30 122 1995-12-31 219 1996-06-30 200 1996-12-31 188 1997-06-30 198 1997-12-31 168 1998-06-30 160 1998-12-31 233 1999-06-30 77