Bi-annual US dollars 1987-06-30 23 1987-12-31 17 1988-06-30 14 1988-12-31 105 1989-06-30 118 1989-12-31 190 1990-06-30 180 1990-12-31 164 1991-06-30 198 1991-12-31 211 1992-06-30 211 1992-12-31 251 1993-06-30 173 1993-12-31 245 1994-06-30 215 1994-12-31 189 1995-06-30 196 1995-12-31 245 1996-06-30 249 1996-12-31 262 1997-06-30 221 1997-12-31 23 1998-06-30 33 1998-12-31 47 1999-06-30 16