| 序号 | 时间 (年) |
数据 (美元) |
|---|---|---|
| 1 | 2011 | |
| 2 | 2010 | |
| 3 | 2009 | |
| 4 | 2008 | |
| 5 | 2007 | |
| 6 | 2006 | |
| 7 | 2005 | 1573.08 |
| 8 | 2004 | 1523.88 |
| 9 | 2003 | 1523.32 |
| 10 | 2002 | 1598.42 |
| 11 | 2001 | 1581.03 |
| 12 | 2000 | 1462.74 |
| 13 | 1999 | 1499.55 |
| 14 | 1998 | 1499.98 |
| 15 | 1997 | 1477.29 |
| 16 | 1996 | 1362.15 |
| 17 | 1995 | 1284.94 |
| 18 | 1994 | 1292.30 |
| 19 | 1993 | 1075.95 |
| 20 | 1992 | 955.46 |
