| 时间 | 值 （亿美元） | 世界排名 |
|---|---|---|
| 2016 | 17 | 62 |
| 2015 | 16 | 102 |
| 2014 | 17 | 109 |
| 2013 | 16 | 111 |
| 2012 | 15 | 111 |
| 2011 | 14 | 110 |
| 2010 | 13 | 105 |
| 2009 | 10 | 105 |
| 2008 | 11 | 109 |
| 2007 | 9 | 110 |
| 2006 | 7 | 114 |
| 2005 | 6 | 117 |
| 2004 | 5 | 107 |
| 2003 | 3 | 118 |
| 2002 | 3 | 116 |
| 2001 | 3 | 112 |
| 2000 | 2 | 123 |
| 1999 | 2 | 119 |
| 1998 | 2 | 117 |
| 1997 | 2 | 120 |
| 1996 | 1 | 122 |
| 1995 | 1 | 128 |
| 1994 | 0 | 130 |
| 1993 | 0 | 128 |