Bi-annual US dollars 1987-06-30 306 1987-12-31 249 1988-06-30 271 1988-12-31 226 1989-06-30 226 1989-12-31 176 1990-06-30 248 1990-12-31 156 1991-06-30 89 1991-12-31 162 1992-06-30 299 1992-12-31 217 1993-06-30 1118 1993-12-31 1290 1994-06-30 1509 1994-12-31 2212 1995-06-30 2090 1995-12-31 1746 1996-06-30 2298 1996-12-31 2837 1997-06-30 3435 1997-12-31 2600 1998-06-30 3503 1998-12-31 3360 1999-06-30 2581