Bi-annual US dollars 1987-06-30 214 1987-12-31 289 1988-06-30 206 1988-12-31 260 1989-06-30 467 1989-12-31 218 1990-06-30 230 1990-12-31 278 1991-06-30 235 1991-12-31 252 1992-06-30 141 1992-12-31 112 1993-06-30 336 1993-12-31 170 1994-06-30 106 1994-12-31 341 1995-06-30 437 1995-12-31 540 1996-06-30 168 1996-12-31 163 1997-06-30 584 1997-12-31 408 1998-06-30 495 1998-12-31 443 1999-06-30 419