| 时间 | 值 （亿美元） | 世界排名 |
|---|---|---|
| 2016 | 65 | 29 |
| 2015 | 17 | 73 |
| 2014 | 80.9 | 33 |
| 2013 | 73.6 | 37 |
| 2012 | 94.3 | 33 |
| 2011 | 41.9 | 52 |
| 2010 | 101.7 | 31 |
| 2009 | 52.7 | 41 |
| 2008 | 88.2 | 41 |
| 2007 | 138.2 | 33 |
| 2006 | 71.3 | 41 |
| 2005 | 137.3 | 20 |
| 2004 | 64.2 | 26 |
| 2003 | 20.2 | 42 |
| 2002 | 85 | 17 |
| 2001 | 56.4 | 24 |
| 2000 | 49.9 | 29 |
| 1999 | 63.1 | 25 |
| 1998 | 37 | 29 |
| 1997 | 12.9 | 45 |
| 1996 | 14.4 | 37 |
| 1995 | 25.7 | 24 |
| 1994 | 8.8 | 38 |
| 1993 | 6.5 | 39 |