Bi-annual US dollars 1987-06-30 363 1987-12-31 315 1988-06-30 326 1988-12-31 476 1989-06-30 470 1989-12-31 353 1990-06-30 457 1990-12-31 658 1991-06-30 397 1991-12-31 407 1992-06-30 611 1992-12-31 403 1993-06-30 692 1993-12-31 928 1994-06-30 1145 1994-12-31 4110 1995-06-30 4394 1995-12-31 4269 1996-06-30 5806 1996-12-31 4913 1997-06-30 4380 1997-12-31 1344 1998-06-30 1164 1998-12-31 980 1999-06-30 796