| 时间 | 值 （亿美元） | 世界排名 |
|---|---|---|
| 2015 | 440.1 | 13 |
| 2014 | 345.8 | 12 |
| 2013 | 281.5 | 16 |
| 2012 | 240 | 20 |
| 2011 | 365 | 13 |
| 2010 | 274 | 18 |
| 2009 | 355.8 | 11 |
| 2008 | 434.1 | 14 |
| 2007 | 252.3 | 23 |
| 2006 | 200.3 | 23 |
| 2005 | 72.7 | 36 |
| 2004 | 54.3 | 29 |
| 2003 | 36.8 | 33 |
| 2002 | 52.1 | 23 |
| 2001 | 51.3 | 25 |
| 2000 | 35.8 | 33 |
| 1999 | 21.7 | 36 |
| 1998 | 26.3 | 35 |
| 1997 | 35.8 | 28 |
| 1996 | 24.3 | 28 |
| 1995 | 21.4 | 27 |
| 1994 | 9.7 | 36 |
| 1993 | 5.5 | 44 |
| 1992 | 2.8 | 44 |
| 1991 | 0.7 | 66 |
| 1990 | 2.4 | 40 |
| 1989 | 2.5 | 36 |
| 1988 | 0.9 | 52 |
| 1987 | 2.1 | 32 |
| 1986 | 1.2 | 38 |