Bi-annual US dollars 1987-06-30 324 1987-12-31 215 1988-06-30 246 1988-12-31 190 1989-06-30 256 1989-12-31 287 1990-06-30 415 1990-12-31 519 1991-06-30 842 1991-12-31 1081 1992-06-30 1037 1992-12-31 885 1993-06-30 1127 1993-12-31 1132 1994-06-30 1569 1994-12-31 1857 1995-06-30 2186 1995-12-31 3158 1996-06-30 3229 1996-12-31 4497 1997-06-30 4646 1997-12-31 5049 1998-06-30 4390 1998-12-31 4431 1999-06-30 3748