Bi-annual US dollars 1987-06-30 268 1987-12-31 302 1988-06-30 287 1988-12-31 295 1989-06-30 268 1989-12-31 297 1990-06-30 349 1990-12-31 338 1991-06-30 293 1991-12-31 306 1992-06-30 293 1992-12-31 230 1993-06-30 224 1993-12-31 192 1994-06-30 190 1994-12-31 152 1995-06-30 142 1995-12-31 122 1996-06-30 101 1996-12-31 152 1997-06-30 176 1997-12-31 201 1998-06-30 190 1998-12-31 196 1999-06-30 151