| 时间 | 值 （亿美元） | 世界排名 |
|---|---|---|
| 2012 | 201.6 | 41 |
| 2011 | 219.9 | 40 |
| 2010 | 371.1 | 37 |
| 2009 | 528.1 | 35 |
| 2008 | 696.4 | 36 |
| 2007 | 530.8 | 40 |
| 2006 | 474.6 | 40 |
| 2005 | 253.9 | 42 |
| 2004 | 56.1 | 46 |
| 2003 | 32.8 | 46 |
| 2002 | 25.6 | 45 |
| 2001 | 39 | 43 |
| 2000 | 111.2 | 38 |
| 1999 | 90.4 | 40 |
| 1998 | 50.3 | 43 |
| 1997 | 58.6 | 45 |
| 1996 | 24.6 | 46 |
| 1995 | 6.8 | 48 |
| 1994 | 7.6 | 47 |
| 1993 | 1.7 | 50 |
| 1992 | 2 | 45 |
| 1991 | 1.4 | 43 |
| 1990 | 1.3 | 38 |
| 1989 | 0.9 | 40 |
| 1988 | 0.6 | 39 |