Bi-annual US dollars 1987-06-30 73 1987-12-31 87 1988-06-30 114 1988-12-31 262 1989-06-30 316 1989-12-31 271 1990-06-30 241 1990-12-31 262 1991-06-30 219 1991-12-31 301 1992-06-30 333 1992-12-31 291 1993-06-30 357 1993-12-31 384 1994-06-30 502 1994-12-31 818 1995-06-30 875 1995-12-31 1008 1996-06-30 1280 1996-12-31 2066 1997-06-30 2216 1997-12-31 2325 1998-06-30 2524 1998-12-31 2731 1999-06-30 2821