Bi-annual US dollars 1987-06-30 81 1987-12-31 79 1988-06-30 84 1988-12-31 139 1989-06-30 64 1989-12-31 76 1990-06-30 87 1990-12-31 87 1991-06-30 68 1991-12-31 155 1992-06-30 234 1992-12-31 280 1993-06-30 312 1993-12-31 304 1994-06-30 252 1994-12-31 191 1995-06-30 299 1995-12-31 211 1996-06-30 325 1996-12-31 168 1997-06-30 218 1997-12-31 201 1998-06-30 193 1998-12-31 268 1999-06-30 336