Bi-annual US dollars 1987-06-30 161 1987-12-31 255 1988-06-30 229 1988-12-31 213 1989-06-30 453 1989-12-31 134 1990-06-30 429 1990-12-31 438 1991-06-30 285 1991-12-31 413 1992-06-30 354 1992-12-31 342 1993-06-30 495 1993-12-31 338 1994-06-30 363 1994-12-31 145 1995-06-30 205 1995-12-31 250 1996-06-30 376 1996-12-31 260 1997-06-30 -18 1997-12-31 107 1998-06-30 73 1998-12-31 -150 1999-06-30 159