Bi-annual US dollars 1987-06-30 0 1987-12-31 0 1988-06-30 0 1988-12-31 0 1989-06-30 0 1989-12-31 0 1990-06-30 0 1990-12-31 0 1991-06-30 0 1991-12-31 0 1992-06-30 0 1992-12-31 0 1993-06-30 0 1993-12-31 118 1994-06-30 130 1994-12-31 269 1995-06-30 247 1995-12-31 209 1996-06-30 182 1996-12-31 134 1997-06-30 366 1997-12-31 232 1998-06-30 549 1998-12-31 221 1999-06-30 243