| 时间 | 值 （亿美元） | 世界排名 |
|---|---|---|
| 2016 | 9.7 | 107 |
| 2015 | 9.1 | 130 |
| 2014 | 8.8 | 133 |
| 2013 | 8.6 | 135 |
| 2012 | 8.1 | 137 |
| 2011 | 7.7 | 138 |
| 2010 | 7.1 | 149 |
| 2009 | 6.3 | 138 |
| 2008 | 5.2 | 140 |
| 2007 | 5 | 137 |
| 2006 | 2.7 | 139 |
| 2005 | 2.9 | 134 |
| 2004 | 2.8 | 132 |
| 2003 | 3 | 131 |
| 2002 | 2.8 | 130 |
| 2001 | 2.6 | 130 |
| 2000 | 2.4 | 128 |
| 1999 | 2.1 | 123 |
| 1998 | 1.8 | 124 |
| 1997 | 2 | 123 |
| 1996 | 1.9 | 122 |
| 1995 | 1.5 | 121 |
| 1994 | 2 | 112 |
| 1993 | 1.2 | 115 |