Bi-annual US dollars 1987-06-30 189 1987-12-31 232 1988-06-30 148 1988-12-31 136 1989-06-30 158 1989-12-31 155 1990-06-30 159 1990-12-31 156 1991-06-30 227 1991-12-31 159 1992-06-30 211 1992-12-31 189 1993-06-30 249 1993-12-31 544 1994-06-30 304 1994-12-31 191 1995-06-30 218 1995-12-31 281 1996-06-30 356 1996-12-31 378 1997-06-30 591 1997-12-31 579 1998-06-30 689 1998-12-31 1539 1999-06-30 970