| 时间 | 值 （亿美元） | 世界排名 |
|---|---|---|
| 2012 | 266.2 | 36 |
| 2011 | 361.4 | 35 |
| 2010 | 312.1 | 38 |
| 2009 | 457.8 | 37 |
| 2008 | 825.5 | 35 |
| 2007 | 1444.8 | 30 |
| 2006 | 702.3 | 35 |
| 2005 | 416.4 | 38 |
| 2004 | 376.7 | 35 |
| 2003 | 217.2 | 35 |
| 2002 | 203.3 | 35 |
| 2001 | 272.8 | 29 |
| 2000 | 543.7 | 26 |
| 1999 | 408 | 29 |
| 1998 | 475.8 | 24 |
| 1997 | 209.3 | 32 |
| 1996 | 71.5 | 38 |
| 1995 | 42.3 | 39 |
| 1994 | 52.7 | 35 |
| 1993 | 48.3 | 34 |
| 1992 | 34.6 | 33 |
| 1991 | 28.2 | 33 |
| 1990 | 16.9 | 32 |
| 1989 | 19.1 | 30 |
| 1988 | 11.4 | 27 |