Bi-annual US dollars 1987-06-30 216 1987-12-31 257 1988-06-30 251 1988-12-31 282 1989-06-30 293 1989-12-31 335 1990-06-30 361 1990-12-31 396 1991-06-30 358 1991-12-31 260 1992-06-30 276 1992-12-31 333 1993-06-30 287 1993-12-31 324 1994-06-30 360 1994-12-31 407 1995-06-30 460 1995-12-31 518 1996-06-30 1029 1996-12-31 978 1997-06-30 968 1997-12-31 859 1998-06-30 774 1998-12-31 749 1999-06-30 626