Bi-annual	US dollars
1987-06-30	282
1987-12-31	277
1988-06-30	259
1988-12-31	188
1989-06-30	180
1989-12-31	194
1990-06-30	225
1990-12-31	253
1991-06-30	251
1991-12-31	254
1992-06-30	234
1992-12-31	153
1993-06-30	215
1993-12-31	168
1994-06-30	181
1994-12-31	196
1995-06-30	167
1995-12-31	144
1996-06-30	289
1996-12-31	180
1997-06-30	288
1997-12-31	275
1998-06-30	615
1998-12-31	662
1999-06-30	547