| 时间 | 值 （亿美元） | 世界排名 |
|---|---|---|
| 2012 | 673.4 | 31 |
| 2011 | 1055.2 | 31 |
| 2010 | 1333.7 | 26 |
| 2009 | 882.9 | 29 |
| 2008 | 1091.6 | 31 |
| 2007 | 1134.6 | 35 |
| 2006 | 887.7 | 31 |
| 2005 | 598.9 | 33 |
| 2004 | 462.3 | 31 |
| 2003 | 415.6 | 32 |
| 2002 | 552.5 | 21 |
| 2001 | 297.9 | 28 |
| 2000 | 233.9 | 30 |
| 1999 | 154.6 | 34 |
| 1998 | 112.6 | 35 |
| 1997 | 107.1 | 40 |
| 1996 | 80.5 | 37 |
| 1995 | 91.6 | 33 |
| 1994 | 251.1 | 23 |
| 1993 | 303.3 | 21 |
| 1992 | 146.9 | 23 |
| 1991 | 83.9 | 24 |
| 1990 | 55.4 | 26 |
| 1989 | 39.1 | 26 |
| 1988 | 24.5 | 25 |