| 时间 | 值 （亿美元） | 世界排名 |
|---|---|---|
| 2012 | 230 | 39 |
| 2011 | 214 | 41 |
| 2010 | 418.1 | 36 |
| 2009 | 699.3 | 32 |
| 2008 | 1227.4 | 28 |
| 2007 | 1207 | 33 |
| 2006 | 558.9 | 37 |
| 2005 | 940.1 | 29 |
| 2004 | 486.1 | 30 |
| 2003 | 527.3 | 28 |
| 2002 | 216.5 | 34 |
| 2001 | 114.6 | 35 |
| 2000 | 42.1 | 46 |
| 1999 | 60.6 | 44 |
| 1998 | 93.3 | 40 |
| 1997 | 345.8 | 27 |
| 1996 | 192 | 31 |
| 1995 | 63.9 | 35 |
| 1994 | 19.5 | 43 |
| 1993 | 26.1 | 38 |
| 1989 | 17.1 | 31 |
| 1988 | 25.4 | 24 |