Bi-annual US dollars 1987-06-30 61 1987-12-31 30 1988-06-30 34 1988-12-31 195 1989-06-30 96 1989-12-31 266 1990-06-30 185 1990-12-31 102 1991-06-30 83 1991-12-31 134 1992-06-30 173 1992-12-31 114 1993-06-30 86 1993-12-31 47 1994-06-30 90 1994-12-31 177 1995-06-30 226 1995-12-31 282 1996-06-30 261 1996-12-31 591 1997-06-30 484 1997-12-31 240 1998-06-30 193 1998-12-31 305 1999-06-30 180