Bi-annual US dollars 1987-06-30 137 1987-12-31 208 1988-06-30 217 1988-12-31 188 1989-06-30 284 1989-12-31 276 1990-06-30 251 1990-12-31 228 1991-06-30 224 1991-12-31 233 1992-06-30 249 1992-12-31 230 1993-06-30 225 1993-12-31 256 1994-06-30 205 1994-12-31 264 1995-06-30 68 1995-12-31 98 1996-06-30 132 1996-12-31 116 1997-06-30 151 1997-12-31 122 1998-06-30 157 1998-12-31 140 1999-06-30 178