| 时间 | 值 （亿美元） | 世界排名 |
|---|---|---|
| 2012 | 472.1 | 33 |
| 2011 | 387.3 | 34 |
| 2010 | 481.2 | 34 |
| 2009 | 255.3 | 41 |
| 2008 | 1045.2 | 33 |
| 2007 | 1214.2 | 32 |
| 2006 | 795.7 | 34 |
| 2005 | 459 | 36 |
| 2004 | 238.3 | 37 |
| 2003 | 108.1 | 37 |
| 2002 | 58.2 | 41 |
| 2001 | 72.5 | 39 |
| 2000 | 93.9 | 40 |
| 1999 | 116.9 | 37 |
| 1998 | 175.9 | 31 |
| 1997 | 121.5 | 37 |
| 1996 | 205.3 | 30 |
| 1995 | 257.6 | 23 |
| 1994 | 163.8 | 25 |
| 1993 | 65.6 | 33 |
| 1992 | 49.3 | 30 |
| 1991 | 70.4 | 26 |
| 1990 | 186.1 | 16 |
| 1989 | 117.1 | 20 |
| 1988 | 20.3 | 26 |