Bi-annual	US dollars
1987-06-30	897
1987-12-31	1296
1988-06-30	1192
1988-12-31	1036
1989-06-30	1212
1989-12-31	1188
1990-06-30	1170
1990-12-31	1316
1991-06-30	1197
1991-12-31	1283
1992-06-30	1709
1992-12-31	1442
1993-06-30	1598
1993-12-31	1938
1994-06-30	2174
1994-12-31	2102
1995-06-30	2296
1995-12-31	2075
1996-06-30	2237
1996-12-31	2594
1997-06-30	3143
1997-12-31	3468
1998-06-30	3866
1998-12-31	3273
1999-06-30	5035