| 时间 | 值 （亿美元） | 世界排名 |
|---|---|---|
| 2012 | 1245 | 26 |
| 2011 | 1289.1 | 28 |
| 2010 | 902 | 31 |
| 2009 | 729.7 | 31 |
| 2008 | 852.1 | 34 |
| 2007 | 1500 | 29 |
| 2006 | 669 | 36 |
| 2005 | 499.8 | 35 |
| 2004 | 598.8 | 29 |
| 2003 | 501.4 | 29 |
| 2002 | 276.2 | 31 |
| 2001 | 207.7 | 33 |
| 2000 | 585 | 25 |
| 1999 | 485.1 | 27 |
| 1998 | 298.9 | 29 |
| 1997 | 1532.9 | 18 |
| 1996 | 1735.7 | 12 |
| 1995 | 768.2 | 15 |
| 1994 | 1264.6 | 11 |
| 1993 | 1536.6 | 8 |
| 1992 | 217.3 | 17 |
| 1991 | 106.6 | 21 |
| 1990 | 108.7 | 21 |
| 1989 | 68.9 | 24 |
| 1988 | 26.2 | 23 |