| 时间 | 值 （亿美元） | 世界排名 |
|---|---|---|
| 2016 | 24.5 | 39 |
| 2015 | 29.2 | 60 |
| 2014 | 3.2 | 136 |
| 2013 | 5.8 | 105 |
| 2012 | 33.2 | 57 |
| 2011 | 78 | 39 |
| 2010 | 92.5 | 34 |
| 2009 | 14.4 | 77 |
| 2008 | 148.4 | 27 |
| 2007 | 356 | 21 |
| 2006 | 250.2 | 17 |
| 2005 | 218.1 | 15 |
| 2004 | 74.6 | 21 |
| 2003 | 9.1 | 61 |
| 2002 | -5 | 191 |
| 2001 | 4.2 | 73 |
| 2000 | 7.4 | 57 |
| 1999 | 8.6 | 51 |
| 1998 | 2.8 | 78 |
| 1997 | 0.8 | 109 |
| 1996 | 2.9 | 65 |
| 1995 | 1.3 | 74 |
| 1994 | 1.5 | 68 |
| 1993 | 0.6 | 90 |
| 1992 | 0.4 | 82 |
| 1991 | 0.8 | 65 |
| 1990 | 0.5 | 72 |
| 1989 | 0.5 | 61 |
| 1988 | 0.4 | 64 |
| 1987 | 0.2 | 73 |
| 1986 | 0.2 | 63 |