Bi-annual US dollars 1987-06-30 18 1987-12-31 8 1988-06-30 7 1988-12-31 13 1989-06-30 65 1989-12-31 13 1990-06-30 72 1990-12-31 137 1991-06-30 68 1991-12-31 80 1992-06-30 183 1992-12-31 129 1993-06-30 144 1993-12-31 151 1994-06-30 198 1994-12-31 349 1995-06-30 256 1995-12-31 279 1996-06-30 370 1996-12-31 276 1997-06-30 298 1997-12-31 283 1998-06-30 452 1998-12-31 616 1999-06-30 527