| 时间 | 值 （亿美元） | 世界排名 |
|---|---|---|
| 2015 | 30.5 | 59 |
| 2014 | 8.5 | 98 |
| 2013 | 45.1 | 41 |
| 2012 | 81.8 | 38 |
| 2011 | 72.1 | 42 |
| 2010 | 64.5 | 42 |
| 2009 | 47.7 | 44 |
| 2008 | 107 | 33 |
| 2007 | 101.9 | 38 |
| 2006 | 56 | 44 |
| 2005 | 78.1 | 34 |
| 2004 | 17.2 | 50 |
| 2003 | 14.2 | 52 |
| 2002 | 6.9 | 64 |
| 2001 | 7.9 | 56 |
| 2000 | 6 | 61 |
| 1999 | 5 | 65 |
| 1998 | 7.4 | 56 |
| 1997 | 6.2 | 57 |
| 1996 | 5.2 | 50 |
| 1995 | 2.7 | 60 |
| 1994 | 1.6 | 66 |
| 1993 | 2 | 59 |
| 1992 | 2 | 47 |