| 时间 | 值 （亿美元） | 世界排名 |
|---|---|---|
| 2016 | 1.1 | 113 |
| 2015 | 1.1 | 119 |
| 2014 | 1.2 | 121 |
| 2013 | 1.3 | 122 |
| 2012 | 1.2 | 121 |
| 2011 | 1.3 | 117 |
| 2010 | 1.3 | 115 |
| 2009 | 1.6 | 108 |
| 2008 | 1.7 | 109 |
| 2007 | 1.6 | 109 |
| 2006 | 1.3 | 112 |
| 2005 | 1.3 | 106 |
| 2004 | 1.4 | 100 |
| 2003 | 1.2 | 102 |
| 2002 | 1.1 | 97 |
| 2001 | 2.3 | 78 |
| 2000 | 0.7 | 101 |
| 1999 | 0.7 | 103 |
| 1998 | 0.8 | 99 |
| 1997 | 0.8 | 100 |
| 1996 | 1.3 | 85 |