| 时间 | 值 （亿美元） | 世界排名 |
|---|---|---|
| 2012 | 148.4 | 44 |
| 2011 | 247.1 | 38 |
| 2010 | 431.1 | 35 |
| 2009 | 517.2 | 36 |
| 2008 | 481.7 | 40 |
| 2007 | 1515.3 | 27 |
| 2006 | 1074.8 | 29 |
| 2005 | 652.6 | 31 |
| 2004 | 434.9 | 33 |
| 2003 | 385.9 | 33 |
| 2002 | 248.7 | 33 |
| 2001 | 373.8 | 26 |
| 2000 | 951.1 | 20 |
| 1999 | 1887.2 | 17 |
| 1998 | 468.4 | 25 |
| 1997 | 210.3 | 31 |
| 1996 | 82.8 | 36 |
| 1995 | 60.9 | 37 |
| 1994 | 51.4 | 37 |
| 1993 | 27.1 | 37 |
| 1992 | 16 | 39 |
| 1991 | 24.4 | 34 |
| 1990 | 39.2 | 29 |
| 1989 | 5.5 | 35 |
| 1988 | 3.1 | 33 |