Bi-annual US dollars 1987-06-30 813 1987-12-31 1021 1988-06-30 1407 1988-12-31 1441 1989-06-30 972 1989-12-31 647 1990-06-30 319 1990-12-31 162 1991-06-30 438 1991-12-31 162 1992-06-30 320 1992-12-31 247 1993-06-30 143 1993-12-31 173 1994-06-30 221 1994-12-31 413 1995-06-30 474 1995-12-31 754 1996-06-30 657 1996-12-31 921 1997-06-30 1211 1997-12-31 1171 1998-06-30 2533 1998-12-31 2335 1999-06-30 2450