Bi-annual	US dollars
1987-06-30	947
1987-12-31	1162
1988-06-30	953
1988-12-31	1166
1989-06-30	1346
1989-12-31	1401
1990-06-30	1488
1990-12-31	1702
1991-06-30	1226
1991-12-31	1774
1992-06-30	1458
1992-12-31	1488
1993-06-30	1122
1993-12-31	686
1994-06-30	869
1994-12-31	1093
1995-06-30	969
1995-12-31	692
1996-06-30	1120
1996-12-31	952
1997-06-30	1499
1997-12-31	2066
1998-06-30	2499
1998-12-31	2225
1999-06-30	2523