Bi-annual US dollars 1987-06-30 35 1987-12-31 143 1988-06-30 162 1988-12-31 202 1989-06-30 161 1989-12-31 134 1990-06-30 181 1990-12-31 139 1991-06-30 154 1991-12-31 176 1992-06-30 135 1992-12-31 167 1993-06-30 140 1993-12-31 124 1994-06-30 190 1994-12-31 210 1995-06-30 186 1995-12-31 216 1996-06-30 228 1996-12-31 339 1997-06-30 414 1997-12-31 380 1998-06-30 255 1998-12-31 393 1999-06-30 184